bluuebunny/crossref_metadata_2025 huggingface dataset:
Diseases resulting from mitochondrial DNA point mutations
Authors: Wallace D. C. , Lott M. T. , Shoffner J. M. , Brown M. D.
Published: June 2005

A number of mitochondrial DNA (mtDNA) mutations have been identified which cause familial, late onset neuromuscular degenerative diseases. These include missense mutations in most of the mtDNA polypeptide genes as well as base substitutions in several tRNA genes. Missense mutations in the mitochondrial electron‐transport genes cause Leber hereditary optic neuropathy. Ten mutations have been associated with this disease, but four at nps 11 178, 3460, 4160 and 15 257 appear sufficient in themselves to cause the disease. One missense mutation in the ATPase 6 gene at np 8993 causes a second phenotype, neurogenic muscle weakness, ataxia and retinitis pigmentosum. Transfer RNA mutations have been identified for myoclonic epilepsy and ragged‐red fibre disease in the tRNALys gene at np 8344 and for the mitochondrial encephalomyopathy, lactic acidosis and stroke‐like episodes syndrome and for maternal mitochondrial myopathy and cardiomyopathy syndrome in the tRNALeu(UUR) gene at nps 3234 and 3260, respectively. Deficiencies in mitochondrial oxidative phosphorylation enzymes have been observed in several common neurodegenerative diseases such as Alzheimer and Parkinson diseases. Perhaps mtDNA mutations play a role in these as well.
Isolation of cDNA sequences around the chromosomal breakpoint in a female with lowe syndrome by direct screening of cDNA libraries with yeast artificial chromosomes
Authors: Okabe I. , Attree O. , Bailey L. C. , Nelson D. L. , Nussbaum R. L.
Published: June 2005

The Lowe oculocerebrorenal syndrome (OCRL; McKusick 309000) is an X‐linked disorder characterized by congenital cataracts, muscular hypotonia, mental retardation, and Fanconi syndrome of the renal tubules. A pair of yeast artificial chromosomes (YACs) that span the Xq25‐q26 translocation breakpoint in a female with OCRL were used as probes to screen cDNA libraries made from bovine lens and human kidney. The methods used to prepare the YACs as probes and to screen the libraries are presented in detail. Two different transcripts were found that map to the region around the Xq25‐q26 breakpoint. These transcripts are now being studied to determine whether one or the other is a candidate gene for OCRL.
Genetic and clinical correlations of Xp21 muscular dystrophy
Authors: Bushby K. M. D.
Published: June 2005

We have investigated over 100 patients with Xp21 muscular dystrophy, drawing together the results of detailed clinical, genetic and dystrophin investigations. A spectrum of disease severity was confirmed, with the most homogeneous clinical groups being at either end of the spectrum, represented by the typical Duchenne and Becker phenotypes. The groups in between showed clinical heterogeneity, and variability in the genetic and dystrophin results. While an out‐of‐frame deletion in association with undetectable dystrophin is most likely to predict the most severe phenotype, and increasing abundance of dystrophin is associated generally with a milder clinical course, no value of dystrophin abundance reliably predicts a particular phenotype. However, deletions of the dystrophin gene involving exons 45–47 and 45–48 especially do seem to be consistently associated with the mildest Becker phenotype. Additional factors must play a role in determining the exact clinical course.
The membrane hypothesis of duchenne muscular dystrophy: Quest for functional evidence
Authors: Hutter O. F.
Published: June 2005

(1) The location of dystrophin in normal muscle, its molecular structure and associations, characterize it as a component of the submembrane cytoskeleton. When dystrophin is missing the cystoskeleton will therefore be defective, and it has been supposed that this renders the muscle membrane more vulnerable to mechanical damage. With the discovery of animal strains lacking in dystrophin, this hypothesis has been put to experimental tests. Contradictory results have been obtained by workers using different exercise regimens and different indices of fibre damage.

(2) Direct measurements of the tensile strength of the membrane have been made on patches of cultured myotubes or isolated muscle fibres, and on sarcolemmal vesicles by pipette aspiration. Neither method has revealed a difference in the tensile strength between normal and dystrophic membrane. The most plausible explanation is that the tensile strength of the membrane is a property more of the lipid bilayer than of the cytoskeleton.

(3) In another experimental approach tensile membrane stress has been produced by exposing isolated muscle fibres and myotubes in culture to hypotonic solutions. In such experiments fibres and myotubes lacking dystrophin have been found to lyse more readily than do normal ones. This difference does not conflict with the similarity in tensile strength of normal and dystrophic fibre membranes noted above. Rather, the predisposition to osmotic lysis of dystrophic fibres and myotubes may signify a lower ratio of membrane surface to cell volume, perhaps as a result of loss of some of the spare membrane normally possessed by skeletal muscle fibres and myotubes.

(4) In red blood cells the membrane cytoskeleton functions to maintain membrane deformability and stability. Deficiency in spectrin, the main cytoskeletal component, predisposes red cells to cytoskeletal rupture and membrane loss when they experience shear stress. Skeletal muscle fibres, especially long fibres contracting eccentrically, are susceptible to shear stress as a result of uneven contraction along their length. In that event, fibres lacking dystrophin may similarly shed membrane more readily.
Molecular basis of inherited medium‐chain acyl‐CoA dehydrogenase deficiency causing sudden child death
Authors: Kelly D. P. , Hale D. E. , Rutledge S. L. , Ogden M. L. , Whelan A. J. , Zhang Z. , Strauss A. W.
Published: June 2005

Deficiency of medium‐chain acyl‐CoA dehydrogenase (MCAD) is an important cause of sudden death in children. The majority of surviving individuals with MCAD deficiency studied to date are homozygous for a single point mutation at bp 985 of the MCAD mRNA (A985G). We have now identified a four‐base‐pair deletion in exon 11 of one allele of the MCAD gene in an American child who died of MCAD deficiency. The deletion mutation results in a frameshift and premature termination codon in the mutant MCAD mRNA. The second mutant allele contained the common point mutation A985G, and thus the proband was a compound heterozygote. Protein immunoblot analysis of the child's liver proteins revealed that the mutant MCAD proteins were barely detectable. Allele‐specific oligonucleotide hybridization analysis performed on amplified exon 11 of the child's MCAD gene clearly identified both mutations. MCAD RFLP analysis of the patient's DNA revealed heterozygosity at the Taq I MCAD RFLP site, thus, the two mutations are associated with different haplotypes. Therefore, we have identified a new mutation in the MCAD gene and have developed a nucleic‐acid‐based screening approach which allows thepost mortem identification of MCAD deficiency.
Azelaic and pimelic acids: Metabolic intermediates or artefacts?
Authors: Bennett M. J. , Ragni M. C. , Hood I. , Hale D. E.
Published: June 2005

Azelaic and pimelic acids are excreted in elevated amounts in urine in disorders of mitochondrial β‐oxidation and disorders of peroxisomal β‐oxidation, for which they are of significant diagnostic value. We have detected the presence of azelaic, pimelic and even‐chain‐length dicarboxylic acids (adipic, suberic and sebacic acids) arising artefactually as a result of storage of small sample volumes in plastic containers. Storage of samples for organic acid analysis in glass containers is recommended.
Evaluation of branched‐chain amino acid intake in children with maple syrup urine disease and methylmalonic aciduria
Authors: Parsons H. G. , Carter R. J. , Unrath M. , Snyder F. F.
Published: June 2005

The biochemical and growth responses to dietary branched‐chain amino acid (BCAA) intake were studied in two children; one with a disorder of branched‐chain amino acid metabolism, maple syrup urine disease (MSUD) (McKusick 24860), and another with methylmalonic aciduria (MMA) (McKusick 25100). Biochemical control of MSUD focussed on plasma leucine levels while measurement of plasma ammonia levels was used in MMA. From 0 to 2.75 years both patients exhibited five episodes of toxicity. In each case toxicity was associated with dietary indiscretion or infection. The quantity of protein tolerated was always less in the MMA patient and was approximately 1 g/kg/day. From 1 to 2.75 years each patient's growth velocity approximated their predicted growth channel except during periods of toxicity. In both cases leucine intake, which gave normal growth without toxicity, was always judged to be less than the FAO/WHO recommendations. The BCAA intake of the MMA patient was remarkably stable from 0.5 to 2.75 years and at 2 years of age isoleucine and valine intake approximated the FAO/WHO recommendations. From 2 to 2.75 years BCAA intake (mg/kg/day) of the MSUD patient was less than that of the MMA patient and well below FAO/WHO recommendations. Neuromotor development in both patients is normal.
Retrospective diagnosis of 3‐hydroxydicarboxylic aciduria by analysis of filter paper blood samples
Authors: von Döbeln U. , Venizelos N. , Hagenfeldt L.
Published: June 2005

Five patients with 3‐hydroxydicarboxylic aciduria have been investigated. Two of them had elder siblings who had died unexpectedly in early infancy. Stored filter paper blood samples obtained from the patients and their siblings for neonatal screening were retrieved. Elevated levels of 3‐hydroxy fatty acids were observed in the samples from three of the five patients with 3‐hydroxydicarboxylic aciduria and in the samples from both siblings.
Characterization of three new deletions at the 5′ end of the HPRT structural gene
Authors: Wehnert M. , Herrmann F. H.
Published: June 2005

In a panel of seven unrelated HPRT‐deficient patients three partial deletions of the 5′ end of the HPRT structural gene were identified by Southern blot analysis. The deletions could be defined as the loss of exons 1–3, exons 2–3 and exon 3 respectively. In two of the deletion mutations aberrant restriction fragments occurred.
Carrier detection for Sanfilippo A syndrome
Authors: Stone J. , Brimble A. , Pennock C. A.
Published: June 2005

Leukocytes from 21 obligate carriers in 12 Sanfilippo A families and 49 normal controls were assayed for heparan sulphamidase (EC 3.10.1.1.) at 55°C. At this assay temperature the results show an absolute distinction between heterozygous carriers and the normal controls.
Maternal phenylketonuria
Authors: Koch R. , Gross Friedman E. , Wenz E. , Jew K. , Crowley C. , Donnell G.
Published: June 2005

Pregnant women with untreated phenylketonuria (PKU) with blood phenylalanine levels greater than 1200 µmol/L usually give birth to offspring with congenital birth defects, including microcephaly, cardiac defects and mental retardation. According to Mabry and Levy, hyperphenylalaninaemic (HPA) women with blood phenylalanine levels between 600 and 1200 µmol/L also have an increased risk to their offspring. To study this problem further, the National Institute of Child Health and Human Development has established a collaborative study for 7 years to elucidate a proper treatment programme for these women.
Molecular characterization of Duarte‐1 and Duarte‐2 variants of galactose‐1‐phosphate uridyltransferase
Authors: Podskarbi T. , Kohlmetz T. , Gathof B. S. , Kleinlein B. , Bieger W. P. , Gresser U. , Shin Y. S.
Published: June 2005

The N314D polymorphism was found in two different alleles of the galactose‐1‐phosphate uridyltransferase (GALT) gene, Duarte‐1 (D1) and Duarte‐2 (D2). Although both variants have identical electrophoretic mobility and isoelectrofocusing points, the galactose‐1‐phosphate uridyltransferase (GALT) activity varies: D1 alleles showed 110–130% of the normal RBC activity, but D2 alleles only 40–50%. We found that D1 alleles also carried a silent mutation in exon 7 (L218L) in addition to N314D. In contrast, besides N314D, D2 alleles carried two regulatory mutations, G1105C and G1391A, in introns D and E, respectively. In normal and Q188R alleles none of the above four mutations coexisted. However, some galactosaemia alleles with mutations other than Q188R, such as W316X and E340X of exon 10, also carried the N314D mutation. The W316X alleles existed in cis with the intron mutations (G1105C and G1391A), whereas those with E340X are in cis with L218L. In all cases examined, the intron mutations were not found in D1 alleles and no D2 alleles had the silent mutation of L218L. These results suggest that the decrease in the GALT activity in D2 may be due to regulation of the GALT gene expression. The G1105C site may be critical to the function of erythroid transcription factor NF‐E1, since it flanks the core consensus sequence for one of its binding sites. The G1391A mutation may affect another cis‐acting regulatory sequence. Alternatively, both mutations may be involved in an aberrant splice processing, which possibly results in a low level of correctly spliced mRNA.
Protein kinase C activity, phosphate uptake and endogenous substrate phosphorylation are altered in Zellweger syndrome
Authors: Boneh A.
Published: June 2005

Protein kinase C (PKC) is a key enzyme in lipid‐mediated signal transduction. Regulation of PKC activation is dependent upon the phospholipid constituents of cellular membranes. PKC is also activated by very long‐chain and long‐chaincis‐unsaturated fatty acids. The present study was undertaken as a first step towards elucidating a possible role for PKC in the pathogenesis of Zellweger syndrome, in which there are both perturbation of plasma membrane phospholipids and accumulation of very long‐chain fatty acids. PKC activity, phosphate uptake and endogenous substrate phosphorylation were examined in intact human skin fibroblasts from Zellweger patients. PKC catalytic activity was increased in the membranous fraction of Zellweger cells compared with control cells, with no apparent translocation of the enzyme from the cytosolic to the membranous compartment. Phosphate uptake was increased in both cytosolic and membranous fractions 2.5‐fold and 4.5‐fold, respectively. Several proteins were extensively phosphorylated in Zellweger cells compared with control cells. These findings indicate that PKC activity is perturbed in Zellweger cells, but the exact role of PKC in altered phosphate uptake and protein phosphorylation and its relevance to the pathogenesis of Zellweger syndrome require further study.
Severe hyperprostaglandin E syndrome with hyperthyroidism — studies of pathogenetic mechanisms
Authors: Fellman V. , Pihko H. , Majander A. , Seyberth H. W.
Published: June 2005

Hyperprostaglandin E syndrome is a rare disease usually presenting with renal symptoms such as polyuria, polyhydramnios, hypercalciuria, hypokalaemia, and recurrent episodes of extreme fever, diarrhoea, and convulsions. We report a severe variant of this syndrome with obvious pain and prostaglandin E2 (PGE2)‐stimulated hyperthyroidism, an association not previously described. Urinary excretion of PGE2 and its metabolite 7α‐hydroxy‐5,11‐diketotetranorprosta‐1,16‐dioic acid were markedly increased above normal levels (to 53.3 and 1895 ng/h per 1.73 m2, respectively). We studied oxidative capacity of peroxisomes and mitochondria, the sites where PGE2 oxidation takes place. A generalized mitochondrial disease could be ruled out and no deficiency was found in liver peroxisomal oxidases. The basic pathology of hyperprostaglandin E syndrome remains unsolved.
Carrier detection for sanfilippo A syndrome
Authors: Matalon R. , Deanching M. , Marback R. , Michals K.
Published: June 2005

In Sanfillipo A families, sulphamidase activities in leukocytes and cultured fibroblasts determined at 55°C distinguish between heterozygote‐carriers, normal individuals and the homozygotes.
Substrate inhibition of adenosine phosphorylation in adenosine deaminase deficiency and adenosine‐mediated inhibition of PP‐ribose‐P dependent nucleotide synthesis in hypoxanthine phosphoribosyltransferase deficient erythrocytes
Authors: Snyder F. F. , Dyer C. , Seegmiller J. E. , Goldblum R. M. , Mills G. C. , Schmalstieg F. C.
Published: June 2005

The metabolism of adenosine and its effects on phosphoribosylpyrophosphate, PP‐ribose‐P, dependent nucleotide synthesis were studied using erythrocytes from patients with adenosine deaminase and hypoxanthine phosphoribosyltransferase deficiency as models. The phosphorylation of adenosine was progressively inhibited by concentrations of adenosine greater than 1 µmol L−1 for control and ADA deficient erythrocytes. There was essentially no initial rate of phosphorylation at 30 µmol L−1 adenosine. Adenosine, 1 µmol L−1, also caused a 60% reduction in PP‐ribose‐P concentration in ADA deficient erythrocytes. For HPRT deficient erythrocytes in which ADA activity was blocked by coformycin, 10 µmol L−1 inosine stimulated PP‐ribose‐P dependent nucleotide synthesis from adenine, whereas, 10 µmol L−1 adenosine inhibited nucleotide synthesis. These observations suggest that adenosine phosphorylation and PP‐ribose‐P dependent nucleotide synthesis are inhibited under conditions in which adenosine accumulates, such as in hereditary or pharmacologically induced ADA deficiency.
N‐acetylglutamate synthetase deficiency, a second patient
Authors: Bachmann C. , Brandis M. , Weissenbarth‐Riedel E. , Burghard R. , Colombo J. P.
Published: June 2005

A second patient withN‐acetylglutamate synthetase deficiency is described. The first symptoms were noted at 6 days of age. The course was lethal despite vigorous treatment. The diagnosis was established after death.
Stable isotope dilution analysis ofN‐acetylaspartic acid in CSF, blood, urine and amniotic fluid: Accurate postnatal diagnosis and the potential for prenatal diagnosis of canavan disease
Authors: Jakobs C. , ten Brink H. J. , Langelaar S. A. , Zee T. , Stellaard F. , Macek M. , Sršňová K. , Sršeň Š. , Kleijer W. J.
Published: June 2005

A sensitive and selective analytical technique is described for the determination ofN‐acetylaspartic acid in body fluids using stable isotope dilution in combination with positive chemical ionization mass spectrometry with selected ion monitoring.

Control mean and ranges have been established: in urine 19.5 and 6.6–35.4 µmol/mmol creat.; in plasma 0.44 and 0.17–0.81 µmol/L; in cerebrospinal fluid 1.51 and 0.25–2.83 µmol/L; and in amniotic fluid 1.27 and 0.30–2.55 µmol/L.

In a patient with Canavan disease,N‐acetylaspartic acid concentration was elevated 80‐fold in urine and 20‐fold in plasma compared to the control means. A subsequent pregnancy of the mother was monitored and theN‐acetylaspartic acid concentration in the amniotic fluid was within the control range and a healthy child was born.
Organic acids in aqueous humour and plasma: Post mortem study in infants and diagnosis of enzymopathies
Authors: Coude M. M. , Charpentier C. , Bonnefont J. P. , Cheron G. , Kamoun P.
Published: June 2005

Organic acids have been determined in aqueous humour and plasma by gas chromatography‐mass spectrometry in 38 cases of infant death and 4 cases of inherited metabolic disease: one had a complex fatty‐acid oxidation disorder with a large urinary excretion of adipic acid, the others had a disorder of propionate catabolism with a large urinary excretion of methylmalonic acid. In each case we found in aqueous humour the abnormal metabolite present in urine. Thus aqueous humour could be a suitable material for retrospective diagnosis of inherited metabolic diseases at autopsy in sudden infant death syndrome.
Long‐chain 3‐hydroxyacyl‐CoA dehydrogenase deficiency
Authors: Przyrembel H. , Jakobs C. , Ijlst L. , de Klerk J. B. C. , Wanders R. J. A.
Published: June 2005

A new case of 3‐hydroxyacyl‐CoA dehydrogenase deficiency is described with a relatively benign course.
Uptake and metabolism of radiolabelled GM1‐ganglioside in skin fibroblasts from controls and patients with GM1‐gangliosidosis
Authors: Midorikawa M. , Inui K. , Okada S. , Yabuuchi H. , Ogura K. , Handa S.
Published: June 2005

The uptake and metabolism of [3‐3H‐sphingosine]GM1‐ganglioside was measured in cultured skin fibroblasts from controls and patients with infantile, juvenile and adult GM1‐gangliosidosis. When dissolved in medium with phosphatidylserine, GM1‐ganglioside was efficiently taken up by cultured skin fibroblasts and transferred into lysosomes. A linear increase in GM1‐ganglioside endocytosis was shown with phosphatidylserine concentrations of up to 40γm/ml. A pulse‐chase study revealed that [3H]GM1‐ganglioside was metabolized to GM2‐ganglioside, GM3‐ganglioside, ceramide dihexoside, ceramide monohexoside, ceramide and sphingosine. Sphingosine was recycled to sphingomyelin. In a 20‐h pulse study, cell lines from patients with GM1‐gangliosidosis of infantile, juvenile and adult types hydrolysed 2–5%, 20–44% and 54–58% of the total endocytosed GM1‐ganglioside respectively. These values were lower than in control cells (64.17 ± 5.43% (n=10)). The hydrolysis rates of exogenous [3H]GM1‐ganglioside in cultured fibroblasts from patients with various types of GM1‐gangliosidosis closely reflected the clinical severity.
Content of phenylalanine, tyrosine and their metabolites in CSF in phenylketonuria
Authors: Antoshechkin A. G. , Chentsova T. V. , Tatur V. Yu. , Naritsin D. B. , Railian G. P.
Published: June 2005

By using ion‐exchange chromatography and gas chromatography coupled with mass spectrometry, the content of phenylalanine, tyrosine and their metabolites typical of phenylketonuria (PKU) was determined in the cerebrospinal fluid (CSF) of 8 untreated children with classical PKU and 9 controls. At the same time, plasma and urine were analysed. In PKU the content of phenylalanine is increased on average 23 times in plasma and CSF. The content of phenylalanine and tyrosine in CSF is about 4 times less as compared with plasma. The phenylalanine‐to‐tyrosine ratio is approximately the same for these fluids both in control and in PKU. This indicates that the transport of phenylalanine and tyrosine through the blood‐brain barrier is not disturbed in PKU.

Phenylpyruvate and 4‐hydroxyphenylpyruvate are either not detected or present in very low concentrations in the CSF of children with PKU; their derivatives, phenyllactate and 4‐hydroxyphenyllactate, are present in relatively higher concentrations. This indicates increased metabolic conversion in brain tissues.
Infantile phytanic acid storage disease, a possible variant of Refsum's disease: Three cases, including ultrastructural studies of the liver
Authors: Scotto J. M. , Hadchouel M. , Odievre M. , Laudat M. ‐H. , Saudubray J. ‐M. , Dulac O. , Beucler I. , Beaune P.
Published: June 2005

Three cases of phytanic acid storage disease with symptoms during the first months of life are reported. Hepatomegaly, facial dysmorphia, growth and/or mental retardation and osteopenia were observed in addition to retinitis pigmentosa and neurosensory deafness. The presence of phytanic acid in serum (160–320 µmol/1 (50–100 µg/ml)) was accompanied by hypocholesterolaemia. Electron microscopy showed that a storage material had accumulated in mesenchymal and parenchymal liver cells. Lamellar structures were seen in hepatocytes and other storing cells. These inclusions resembled the structures found in plant chloroplasts containing phytol.

Some of the clinical and biological data obtained were consistent with Refsum's disease. However, other characteristics such as mental retardation, hepatomegaly, osteopenia, hypocholesterolaemia and hypoalphalipoproteinaemia, as well as the ultrastructural findings in the liver, suggested that our patients' illness was either a phytanic acid storage disease different from the classical form of Refsum's disease, or a more severe early symptomatic form of Refsum's disease. Early diagnosis by phytanic acid assay and electron microscopic liver examination calls for prescription of a low phytanate diet in the hope of improving the child's condition.
An occipito‐temporal syndrome in adolescents with optimally controlled hyperphenylalaninaemia
Authors: Lou H. C. , Toft P. B. , Andresen J. , Mikkelsen I. , Olsen B. , Güttler F. , Wieslander S. , Henriksen O.
Published: June 2005

The study included 16 adolescents with optimally controlled hyperphenylalaninaemia (McKusick 26160), of whom six did not require treatment according to conventional criteria. All except the two patients with lowest median serum phenylalanine level throughout childhood (most values at 200–300 µmol/L) had white matter abnormalities detectable with magnetic resonance imaging. The lesions were particularly prominent in the watershed regions between the posterior and middle cerebral arteries. In most patients with moderate or severe hyperphenylalaninaemia frontal white matter lesions were present as well. Normal proton magnetic resonance spectra indicated that the lesions were stable. Occipital EEG abnormalities were frequent, and deficient performance on a pattern‐recognition test was a characteristic neuropsychological finding. Serum phenylalanine levels at about 300 µmol/L or below throughout childhood and early adolescence may be required to avoid lesions. The present study demonstrates the limitations of even an optimally controlled dietary regimen in hyperphenylalaninaemia.
Investigation of enzyme defects in children with lactic acidosis
Authors: Merinero B. , Pérez‐Cerda C. , Ugarte M.
Published: June 2005

Screening for enzyme deficiencies was carried out in cultured skin fibroblasts and leukocytes of 19 patients with lactic acidosis and neurological problems. Pyruvate carboxylase deficiency was demonstrated in three cases. Reduced pyruvate oxidation was found in seven cultures; six showed no significant stimulation of the oxidation rate by methylene blue and in three a decreased pyruvate dehydrogenase complex activity was confirmed. Methylene blue restored a near normal oxidation rate in the seventh culture which had decreased cytochromec oxidase activity.
Prenatal diagnosis of Non‐ketotic hyperglycinaemia
Authors: Toone J. R. , Applegarth D. A. , Levy H. L.
Published: June 2005

Non‐ketotic hyperglycinaemia (NKH) is a devastating neurological disease for which there is no effective therapy. Consequently, most couples with a pregnancy known to be at risk for NKH request prenatal diagnosis. We have applied the combination of chorionic villus (CVS) assay for glycine cleavage enzyme activity and determination of amniotic fluid glycine concentration to increase the reliability of prenatal diagnosis for this disorder beyond that of each of these methods alone. All 15 of the at‐risk pregnancies monitored had CVS glycine cleavage assay and five also had amniotic fluid glycine measurements. Two cases had no detectable cleavage activity in CVS and one gave uninterpretable enzyme results. Amniotic fluid glycine concentration was increased in all three and NKH was confirmed by abortus tissue assays for cleavage activity and amino acids. The remaining 12 case had activity in CVS (two also had normal amniotic fluid glycine levels) and delivered unaffected infants. Four of these 12 cases had cleavage activities below or at the low end of the normal range, perhaps indicating carrier status. We believe that the combination of CVS glycine cleavage assay and amniotic fluid glycine measurement is currently the best approach to the prenatal diagnosis of NKH.
Measurement of acyl‐CoA dehydrogenase activity in cultured skin fibroblasts and blood platelets
Authors: Taylor R. W. , Jackson S. , Pourfarzam M. , Bartlett K. , Turnbull D. M.
Published: June 2005

The measurement of acyl‐CoA dehydrogenase activity is an essential part of the investigation of patients with suspected defects of fatty acid oxidation, and recently the organometallic oxidant ferricenium hexafluorophosphate has been introduced as an electron acceptor for these assays. However, we show that when medium‐chain acyl‐CoA dehydrogenase activity was measured in cultured skin fibroblasts and platelets from patients with proven defects of this enzyme, there was considerable residual enzyme activity when this electron acceptor was used. The ferricenium assay is not as specific as the anaerobic ETF‐linked assay in the biochemical diagnosis of medium‐chain acyl‐CoA dehydrogenase deficiency in fibroblasts, and therefore is of limited clinical applicability in its present form.
N‐acetylglucosamine 6‐sulphatase deficiency in a Nubian goat: A model of Sanfilippo syndrome type D (mucopolysaccharidosis IIID)
Authors: Thompson J. N. , Jones M. Z. , Dawson G. , Huffman P. S.
Published: June 2005

A male Nubian goat (SD‐1) presented at birth with neurological manifestations consistent with a lysosomal storage disease. Histological studies of tissue obtained at autopsy suggested glycosaminoglycan storage. Total urinary glycosaminoglycan levels, as measured by the uronic acid method, were elevated but overlapped with levels in a younger control goat. However,N‐sulphate content was increased 2‐ to 5‐fold, suggestive of heparan sulphate excretion, and this elevation was confirmed by cellulose acetate electrophoresis. Further, urinary levels of freeN‐acetylglucosamine 6‐sulphate were increased 6‐fold over controls, SD‐1 cultured skin fibroblasts, labelled with [35S]sulphate, incorporated twice as much radioactivity into macromolecular material as did normal fibroblasts. Forty‐eight hours after removal of [35S]sulphate from the medium the SD‐1 fibroblasts retained 58% of the label, whereas in control fibroblasts it had declined to 20%, indicative of [35S]proteoglycan storage in SD‐1. The assay of fibroblast extracts revealed a profound deficiency ofN‐acetylglucosamine 6‐sulphatase whereas eight other activities includingβ‐mannosidase, arylsulphatase B, iduronate 2‐sulphatase,N‐acetylgalactosamine 6‐sulphatase, and heparin sulphamidase were normal. Mixing of SD‐1 sonicates with normal sonicates showed no evidence of an inhibitor, and mixing of SD‐1 sonicates with Sanfilippo D cell sonicates yielded no activity. These data ruled out multiple sulphatase deficiency and suggested the first example of the human Sanfilippo syndrome, type D (N‐acetylglucosamine 6‐sulphatase deficiency) in goats.
Serum selenium levels in individuals on PKU diets
Authors: Darling G. , Mathias P. , O'Regan M. , Naughten E.
Published: June 2005

Serum selenium levels in 73 patients with phenylketonuria were significantly lower than in controls. The phenylketonuric and hyperphenylalaninaemic individuals taking the non‐supplemented amino acid mixture generally had lower levels: 36% were below the normal range as defined by our laboratory, compared with 19% in the supplemented group. The low levels were present even in those on diet, who had a greater phenylalanine tolerance — that is, a tolerance for more than 9×50 mg phenylalanine exchanges per day, in other words a higher intake of natural protein. Individuals on long‐term synthetic diets may be at risk for selenium deficiency even on selenium supplements. In areas where the soil may be low in selenium, the deficiency may be aggravated. Long‐term low levels may impair health but the required amount of selenium supplementation remains uncertain.
Sialuria: a second case
Authors: Wilcken B. , Don N. , Greenaway R. , Hammond J. , Sosula L.
Published: June 2005

A case of sialuria is described in a girl who presented in the neonatal period with hepatosplenomegaly, and who has moderate developmental delay at the age of 2 years. There was massive urinary excretion of free sialic acid (N‐acetylneuraminic acid). The clinical, biochemical and ultramicroscopical features were distinct from those described in Salla disease and in infantile sialic acid storage disorder.
Localization of pipecolic acid metabolism in rat liver peroxisomes: Probable explanation for hyperpipecolataemia in Zellweger syndrome
Authors: Trijbels J. M. F. , Monnens L. A. H. , Melis G. , van den Broekvan Essen M. , Bruckwilder M.
Published: June 2005

The metabolism of [14C]pipecolic acid was studied in peroxisomal fractions of rat liver obtained by density gradient centrifugation in Percoll. The production rate of [14CO2] was used to measure the metabolic activity of the fractions towards [14C]carboxypipecolic acid as a substrate. It was shown that this activity was located in the peroxisomal fractions by comparison with the peroxisomal marker enzyme urate oxidase (EC 1.7.3.3). The process was markedly elevated by the addition of FAD. The apparentKm forDL‐pipecolic acid was found to be 1.2 mmol L−1. Addition of ATP (1 mmol L−1) did not influence the decarboxylation rate of pipecolic acid. These results might explain the defective metabolism of pipecolic acid in patients with Zellweger syndrome who are lacking peroxisomes.
Argininosuccinic aciduria: Long‐term treatment with arginine
Authors: Parsons H. G. , Scott R. B. , Pinto A. , Carter R. J. , Snyder F. F.
Published: June 2005

The presentation and 2 year treatment of a patient with argininosuccinic aciduria is reported. Erythrocyte argininosuccinate lyase activity was less than 2% of normal. Long‐term management included protein restriction and arginine dietary supplementation. The child experienced three episodes of hyperammonaemia (>100 µm), the first at birth, the second at 6.5 months and the third at 16 months. Neurological development deteriorated between 14 and 24 months. Hepatomegaly and biochemical hepatitis, a feature of this condition, was accompanied by enlarged mitochondria with tubular paracrystalline inclusions not previously recognized in this disorder.
Phenylketonuria revisited: Treatment of adults with behavioural manifestations
Authors: Brunner R. L. , Brown E. H. , Berry H. K.
Published: June 2005

Dietary treatment of three PKU patients with irreversible changes is described and evaluated.
Cerebrotendinous xanthomatosis: A review of biochemical findings of the patient population in the netherlands
Authors: Koopman B. J. , Wolthers B. G. , van der Molen J. C. , van der Slik W. , Waterreus R. J. , van Spreeken A.
Published: June 2005

This study gives a review of the results obtained from biochemical investigations of 20 patients in The Netherlands suffering from cerebrotendinous xanthomatosis, an inborn error of metabolism in bile acid synthesis. Diagnosis can best be established by determining the excretion of urinary bile alcohols, in particular 5β‐cholestane‐3α,7α,12α,23,25‐pentol, in urine by means of capillary gas chromatography. Measurement of serum cholestanol levels or serum cholestanol/cholesterol ratios, commonly used for establishing cerebrotendinous xanthomatosis, are not reliable. The effectiveness of the different therapies, i.e. administration of bile acids, can be evaluated by monitoring the urinary excretion of bile alcohols. From such investigations it was concluded that cholic acid especially, but also chenodeoxycholic acid are the therapies of choice for the treatment of cerebrotendinous xanthomatosis. All patients, until now diagnosed in The Netherlands were not discovered before the third or fourth decade of life because the characteristic signs only then become manifest clearly. Unfortunately, because sterol storage is almost irreversible, therapy only results in minor improvements of the patient's condition. Therefore early detection of the presence of cerebrotendinous xanthomatosis is desirable so that treatment can start before extensive storage of sterols is a fact. We developed some laboratory assays with the purpose of early detection. One consists of the detection of cerebrotendinous xanthomatosis carriers by subjecting them to oral cholestyramine administration and monitoring the urinary excretion of the bile alcohol 5β‐cholestane‐3α,7α,12α,23,25‐pentol before and after treatment. Secondly, a relatively simple screening test for cerebrotendinous xanthomatosis was developed based on an enzymatic assay of 7α‐hydroxylated steroids in urine. After suitable modification this assay in principle allows the screening of large populations for the existence of cerebrotendinous xanthomatosis and thus to detect the disease at an earlier stage of life.
Effect of the X‐linkedHyp mutation onN‐ethylmaleimide labelling of proteins in renal brush border membrane
Authors: Vizel E. J. , Tenenhouse H. S. , Scriver C. R.
Published: June 2005

The X‐linked dominant mutation, hypophosphataemia (gene symbol,Hyp) is expressed in the laboratory mouse as deficient phosphate transport at the renal brush border membrane (BBM) of proximal nephron. In an attempt to identify proteins which mediate phosphate transport, we treated renal BBM vesicles prepared from mutant male (Hyp/Y) and normal male (+/Y) littermates, with radiolabelledN‐ethylmaleimide (NEM), in the presence or absence of arsenate which is a competitive inhibitor of phosphate transport. Polyacrylamide gel electrophoresis revealed labelling of membrane proteins in the 40–45 kDa range; addition of arsenate during NEM treatment inhibited labelling. These findings indicate a 40–45 kDa protein as a component of the renal BBM phosphate transport system(s). We found no difference between protein labelling of the renal BBM fromHyp/Y and +/Y mice.
Review: Genetics of steroid sulphatase deficiency and X‐linked ichthyosis
Authors: Crawfurd M. A.
Published: June 2005

Steroid sulphatase deficiency which started out as a curious placental microsomal enzyme deficiency associated with low maternal urinary oestrogen excretion and difficulties in delivery, first described only twelve years ago, has now become a generalized enzyme deficiency associated also with a common skin disease. It turns out not only to be inherited in an X‐linked recessive manner, but to be part of a gene cluster which includes the Xg blood group gene and which has been precisely assigned to the distal tip of the short arm of the X‐chromosome. This cluster is unique for genes on the X‐chromosome in escaping X‐inactivation.

It remains to be unequivocally demonstrated whether steroid sulphatase is identical to arylsulphatase C or whether these are two enzymes sharing a common polypeptide chain determined by a single gene. However, Rose (1982) presents evidence that one steroid sulphatase is probably identical with arylsulphatase C. It also remains to be conclusively demonstrated whether the gene for the enzyme deficiency is also that for ichthyosis or whether they are two very closely linked genes. If the former is true the role of steroid sulphatase in the abnormal keratinization of ichthyosis is still to be elucidated. Above all the special nature of the DNA in this unique region awaits description.
Pterins analysis in amniotic fluid for the prenatal diagnosis of GTP cyclohydrolase deficiency
Authors: Dhondt J. ‐L. , Tilmont P. , Ringel J. , Farriaux J. ‐P.
Published: June 2005

Hyperphenylalaninaemia due to tetrahydrobiopterin deficiency is a group of rare and severe diseases. Prenatal diagnosis of dihydropteridine reductase and pyruvoyltetrahydropterin synthetase deficiencies can be achieved by enzyme assay in cultured fluid cells and/or fetal blood. In contrast, prenatal diagnosis of GTP cyclohydrolase deficiency can only rely on the measurement of pterin metabolites in the amniotic fluid.

A pregnancy at risk for GTP cyclohydrolase deficiency was investigated. HPLC analysis of amniotic fluid pterins revealed neopterin and biopterin concentrations below the lowest limit of normal age‐matched gestations. The mother refused abortion. The early follow‐up of the child confirmed the diagnosis of GTP cyclohydrolase deficiency (hyperphenylalaninaemia, abnormal profile of urinary pterins and neurological deterioration).
Relationship between plasma and red cell biopterins in acute and chronic hyperphenylalaninaemia
Authors: Leeming R. J. , Hall S. K. , Surplice I. M. , Green A.
Published: June 2005

Biopterin concentrations in red blood cells were higher in patients with chronic hyperphenylalaninaemia than following a single oral dose of phenylalanine, although the plasma concentrations were similar. These findings suggest that tetrahydrobiopterin is synthesized in immature red blood cells in response to hyperphenylalaninaemia. The less marked increase in plasma biopterin suggests slow release from a tissue reservoir. The maintenance of a differential between erythrocyte and plasma biopterin concentrations suggests that some mechanism retains biopterin intracellularly.
Increased plasma pyridoxal‐5′‐phosphate levels before and after pyridoxine loading in carriers of perinatal/infantile hypophosphatasia
Authors: Chodirker B. N. , Coburn S. P. , Seargeant L. E. , Whyte M. P. , Greenberg C. R.
Published: June 2005

We measured plasma levels of pyridoxal‐5′‐phosphate (PLP), a cofactor form of vitamin B6 and apparent natural substrate for alkaline phosphatase (ALP), in carriers and in non‐carriers of the severe perinatal and infantile forms of hypophosphatasia, both before and after an oral load of pyridoxine (i.e. 1/3 mg/kg body weight). The assignment of carrier status was determined by serum ALP activity, level of serum inorganic phosphate, and if necessary urinary phosphoethanolamine excretion. Plasma PLP levels were significantly increased in the carriers both before and especially after B6 loading.
Erythrocytic uridine diphosphate galactose in galactosaemia
Authors: Kirkman H. N.
Published: June 2005

An earlier claim of a deficiency of uridine diphosphate galactose in erythrocytes of galactosaemia patients was not confirmed. Enzymic techniques similar to those of the earlier investigators were used to determine not only the concentration of uridine diphosphate galactose but also the ratio of this concentration to the sum of the uridine sugar diphosphates (uridine diphosphate galactose and uridine diphosphate glucose). The values in erythrocytes of galactosaemic subjects were similar to those of non‐galactosaemic children on a galactose‐restricted diet and to those of normal adults. These results cast doubt on the claim of a major deficiency of uridine diphosphate galactose in galactosaemia and on the need for treating galactosaemic children with uridine.
Animal models for lysosomal storage diseases: A new case of feline mucopolysaccharidosis VI
Authors: Di Natale P. , Annella T. , Daniele A. , Spagnuolo G. , Cerundolo R. , de Caprariis D. , Gravino A. E.
Published: June 2005

Two long‐haired Siamese cats are reported with clinical manifestations of human mucopolysaccharidosis VI (Maroteaux‐Lamy disease): facial dysmorphia, dysostosis multiplex, paralysis. Urine of the two affected animals contained a high concentration of glycosaminoglycans, as detected by the dimethylmethylene blue test. Qualitative analysis, performed by thin‐layer chromatography of the cetylpyridinium chloride‐precipitable material, showed dermatan sulphate. Excessive incorporation of [35S]sulphate in the intracellular mucopolysaccharide of cultured fibroblasts and deficiency of arylsulphatase B in such cells indicate that these cats are affected by Maroteaux‐Lamy disease. They should thus be considered the first European case of feline mucopolysaccharidosis VI.
Maple syrup urine disease: Interrelations between branched‐chain amino‐, oxo‐ and hydroxyacids; implications for treatment; associations with CNS dysmyelination
Authors: Treacy E. , Clow C. L. , Reade T. R. , Chitayat D. , Mamer O. A. , Scriver C. R.
Published: June 2005

Four patients with classical maple syrup urine disease were treated for up to 5885 days per patient with a relaxed protocol allowing branched‐chain amino acid levels in plasma to rise about 5 times the normal mean value. The patients have had satisfactory development and lifestyle. They spent 318 days in hospital during 19 937 aggregate treatment days. Plasma levels of leucine and the corresponding 2‐oxo acid were shown to be elevated disproportionately relative to the other branched‐chain metabolites. Levels of isoleucine and valine were lower than those of leucine apparently because of runout into alternative metabolite pools, namely theR metabolites for isoleucine and the hydroxyacid for valine. The chronic accumulation of branched‐chain 2‐oxo acid(s) in our patients was associated with chronic dysmyelinating changes in CNS visible by imaging. Another patient with a thiamine‐responsive variant of maple syrup urine disease had five acute crises incurring 29 days in hospital in a total of 6910 treatment days. However, she did not have chronic metabolic dyshomeostasis (her average plasma amino acid values were normal) and she had no evidence of dysmyelination. A relaxed treatment protocol for patients with maple syrup urine disease may benefit them in quality of life, but it apparently exacts a cost in metabolic control and CNS pathology.
A synopsis of the unconjugated acidic transamination metabolites of phenylalanine in phenylketonuria
Authors: Langenbeck U. , Behbehani A. , Mench‐Hoinowski A.
Published: June 2005

We present blood and urine levels of unconjugatedo‐hydroxyphenylacetic, phenyllactic and phenylpyruvic acids in 61 children (2 years of age and above) and juveniles with phenylketonuria on or partially off diet. The samples were obtained during 185 scheduled outpatient visits and have been analysed with gas chromatographic methods. The compiled data define reference ranges of phenylalanine transamination capacity and of renal transport of metabolites which may be of value in further studies on the pathogenesis of phenylketonuria.
Lesch‐Nyhan syndrome and its pathogenesis: Purine concentrations in plasma and urine with metabolite profiles in CSF
Authors: Harkness R. A. , McCreanor G. M. , Watts R. W. E.
Published: June 2005

Purine metabolism in the Lesch‐Nyhan syndrome has been re‐examined in 10 patients. Hypoxanthine and xanthine concentrations in plasma and CSF and urinary excretion have been studied, on and off allopurinol treatment, using high performance liquid chromatographic methods. Accumulation of the substrate, hypoxanthine, of the missing hypoxanthine guanine phosphoribosyltransferase (HPRT) enzyme, is more marked in urine and in CSF than in plasma. The greater increase in CSF is consistent with the most metabolically active tissue, brain, showing the most marked functional changes.

The function of HPRT seems to be the recycling of hypoxanthine which is released from tissues in increasing quantities as energy use, ATP ‘turnover’, in the tissue increases. The existing screening method for HPRT deficiency, the ratio of the urinary concentration of urate to that of creatinine, shows overlap between the values in severe HPRT deficiency and in controls; this overlap is not found with a urinary hypoxanthine/creatinine molar concentration ratio.
Aminoacidopathies: A review of 3 years experience of investigations in a Kuwait hospital
Authors: Yadav G. C. , Reavey P. C.
Published: June 2005

We present a summary of the results of quantitative amino acid analysis in 800 subjects over a three‐year period in Al‐Sabah Hospital, Kuwait. Thirty‐five patients with aminoacidopathy were identified, all but two of whom were the offspring of first‐degree consanguineous marriages: nine cases of phenylketonuria, one benign hyperphenylalaninaemia, seven non‐ketotic hyperglycinaemia, five tyrosinaemia, five homocystinuria, four citrullinaemia, two cystinuria, one hyperprolinaemia, and one maple syrup urine disease. The clinical and biochemical findings in these cases are described.