bluuebunny/crossref_metadata_2025 huggingface dataset:
Enzymological characterization of a feline analogue of primary hyperoxaluria type 2: a model for the human disease
Authors: Danpure C. J. , Jennings P. R. , Mistry J. , Chalmers R. A. , McKerrell R. E. , Blakemore W. F. , Heath M. F.
Published: June 2005

This paper concerns an enzymological investigation into a putative feline analogue of the human autosomal recessive disease primary hyperoxaluria type 2. The hepatic activities ofd‐glycerate dehydrogenase, using bothd‐glycerate and hydroxypyruvate as substrates, and glyoxylate reductase, which are the deficient enzyme activities in human primary hyperoxaluria type 2, were markedly depleted in four affected cats (0–6% of controls). The activities of a number of other enzymes, lactate dehydrogenase, glutamate dehydrogenase,d‐amino acid oxidase, aspartate: 2‐oxoglutarate aminotransferase, glutamate: glyoxylate aminotransferase and alanine: glyoxylate aminotransferase (the deficient enzyme in primary hyperoxaluria type 1) were unaltered. The intracellular distribution ofd‐glycerate dehydrogenase and glyoxylate reductase in cat liver was shown to be cytosolic, as they are in human liver. The activities ofd‐glycerate dehydrogenase and glyoxylate reductase were determined in unaffected related cats and putative heterozygotes were identified. The correlation betweend‐glycerate dehydrogenase and glyoxylate reductase activities in the related cats and their combined deficiency in the affected cats confirmed previous suggestions that they are identical gene products.
Neurological deterioration in adult phenylketonuria
Authors: Villasana D. , Butler I. J. , Williams J. C. , Roongta S. M.
Published: June 2005

A 28‐year‐old man with classical phenylketonuria had increased seizure frequency and rapidly progressive spasticity. There was a marked reduction of biogenic amine neutotransmitter metabolites in cerebrospinal fluid. Dietary therapy reduced serum phenylalanine levels, improved symptoms of hypertonicity, and cerebrospinal fluid neurotransmitter metabolites became normal. An adolescent male with classical phenylketonuria, treated by dietary restriction until age 6 years, was assessed for decreasing school performance at 18 years. Cerebrospinal fluid biogenic amine neurotransmitter metabolites were significantly reduced. Magnetic resonance imaging in both subjects showed multiple areas of increased signal intensity in cerebral white matter. Neuropathological changes in classical phenylketonuria have been characterized as a dysmyelinating or demyelinating process. Neurochemical studies show a defect in brain lipids and biogenic amine metabolism. In the past, dietary therapy was directed at reducing hyperphenylalaninaemia only during the first decade of life. This report, as well as other studies, indicates that dietary therapy should be lifelong in patients with classical phenylketonuria, in order to prevent progressive and insidious neurological deterioration in later life.
A specific fluorogenic assay for N‐acetylgalactosamine‐4‐sulphatase activity using immunoadsorption
Authors: Brooks D. A. , Gibson G. J. , McCourt P. A. G. , Hopwood J. J.
Published: June 2005

A method combining immune capture and enzyme detection by fluorochemistry has been developed for the diagnostic assay of N‐acetylgalactosamine‐4‐sulphatase (4‐sulphatase). The procedure uses a monoclonal antibody 4‐S 4.1 to immunoadsorb 4‐sulphatase specifically from complex protein samples containing other sulphatases, and 4‐methylumbelliferyl sulphate to detect captured 4‐sulphatase. The assay provides an accurate and simple method for the diagnosis of Maroteaux‐Lamy syndrome (Mucopolysaccharidosis type VI).
β‐Mannosidase deficiency in a female infant with epileptic encephalopathy
Authors: Cooper A. , Wraith J. E. , Savage W. J. , Thornley M. , Noronha M. J.
Published: June 2005

We report a female infant with an isolated deficiency ofβ‐mannosidase activity. At nine months of age dysmorphism was absent except for brachecephaly. There was moderate developmental delay and a startle response to sound. At 12 months there was a sudden onset of tonic‐clonic seizures which were unresponsive to drug therapy, requiring paralysis and mechanical ventilation for control. The child died suddenly aged 15 months.β‐mannosidase activity was markedly reduced in white cells and cultured skin fibroblasts whilst other lysosomal enzymes were normal. The disaccharide ManGlcNAc was excreted in urine but urinary mucopolysaccharides were normal.
Altered phosphorylation state of branched‐chain 2‐Oxo acid dehydrogenase in a branched‐chain acyltransferase deficient human fibroblast cell line
Authors: Eisenstein R. S. , Hoganson G. , Miller R. H. , Harper A. E.
Published: June 2005

The abundance and phosphorylation state of the polypeptide constitutents of the human branched‐chain 2‐oxo acid dehydrogenase complex were examined in mitochondria from normal and maple syrup urine disease (MSUD) fibroblasts. In normal fibroblast mitochondria two forms of the E1α subunit were observed: non‐phosphorylated (E1α) and phosphorylated (E1α−P). About 40–50% of E1α was present as E1α−P. The ability to quantitate the two forms of E1α permitted examination of the association between decreased capacity to oxidize branched‐chain 2‐oxo acids and the phosphorylation state of E1α.

Changes in phosphorylation state of E1α were observed in MSUD fibroblasts as compared to control cells. Of particular interest was the absence of E1α−P in an MSUD fibroblast line which lacked the dihydrolipoyl acyltransferase (E2) subunit of the dehydrogenase complex. In two MSUD cell lines deficient in E1α, the abundance of E1α−P appeared to be preferentially reduced. A fourth MSUD cell line contained normal quantities of E3, E2 and both forms of the E1α polypeptide. Our results indicate that alterations in the abundance of dehydrogenase complex polypeptides in MSUD fibroblasts may influence the phosphorylation state of the E1α polypeptide. They demonstrate the potential for examining simultaneously mutations which affect both the catalytic and regulatory components of the dehydrogenase complex.
Confocal scanning laser microscopy of mitochondria: a possible tool in the diagnosis of mitochondrial disorders
Authors: Ruiters M. H. J. , van Spronsen E. A. , Skjeldal O. H. , Stromme P. , Scholte H. R. , Pzyrembel H. , Smit G. P. A. , Ruitenbeek W. , Agsteribbe E.
Published: June 2005

This paper describes a non‐invasive method for the study of mitochondrial morphology in cultured human skin fibroblasts by confocal scanning laser microscopy after staining the mitochondria with 2‐[4‐(dimethylaminostyryl]‐1‐methylpyridinium iodide. This method is applied to compare mitochondria in fibroblasts from healthy individuals and from patients with mitochondrial myopathy. In most cases there is a striking swelling of the patient's mitochondria and a loss of fine structure. The results with respect to the potential of this method as a diagnostic tool are discussed.
Increased levels of DHEAS in serum of patients with X‐linked ichthyosis
Authors: Milone A. , Delfino M. , Piccirillo A. , Illiano G. M. P. , Aloj S. M. , Bifulco M.
Published: June 2005

The metabolic basis of X‐linked ichthyosis is a deficiency of steroid sulphatase, a microsomal enzyme which removes sulphate groups from sulphated steroids. We report on a carefully controlled group of 15 patients with recessive X‐linked ichthyosis, selected in a narrow age range (22–33 years), in whom, through the use of gas chromatographic analysis and conventional radioimmunoassay, we have measured not only elevated serum cholesterol sulphate levels but also significantly elevated serum dehydroepiandrosterone sulphate levels. The latter finding has been controversial in previous reports. We believe that the radioimmunoassay procedure generally used should be held responsible for such controversy since it often gives rise to false positive and/or false negative values. Gas chromatography, although more exacting, appears to be far more reliable for the assessment of elevated serum dehydroepiandrosterone.
Sucrase‐isomaltase and cystic fibrosis
Authors: Sips H. J. , Claass A. H. W. , van Dongen J. M. , Willemsen R. , Hoogeveen A. T. , Galjaard H. , Sinaasappel M. , Hauri H. ‐P. , Sterchi E. E.
Published: June 2005

The intestinal microvillar enzyme complex sucrase‐isomaltase has been studied in cystic fibrosis and control ileum. A number of biochemical parameters of the enzyme in ileum homogenates have been determined. Both solubilized as well as membrane‐bound sucrase‐isomaltase were analyzed with respect to their reaction with monoclonal antibodies against human sucrase‐isomaltase. Finally the subcellular localization of sucrase‐isomaltase was verified by immunoelectronmicroscopy or via the analysis of purified brush‐border membrane preparations. At all levels no significant differences could be detected between sucrase‐isomaltase of cystic fibrosis and control ileum. It is concluded that an abnormal subcellular localization and/or abnormal enzymatic activity of sucrase‐isomaltase in cystic fibrosis intestine cannot explain the markedly decreased disaccharidase activities in amniotic fluids from pregnancies resulting in a child affected with cystic fibrosis.
Fructose‐1,6‐diphosphatase deficiency: Diagnosis using leukocytes and detection of heterozygotes with radiochemical and spectrophotometric methods
Authors: Alexander D. , Assaf M. , Khudr A. , Haddad I. , Barakat A.
Published: June 2005

The first two cases of fructose‐1,6‐diphosphatase (FDPase) deficiency from the Middle East have been diagnosed on leukocytes using a spectrophotometric assay and a new radiochemical technique. The control mean for FDPase measured by the spectrophotometric assay was 178.2 nm mg−1 h−1 (n=12), 66.8 nm mg−1 h−1 for obligate heterozygotes (n=4) and non‐detectable in the two patients. By the radiochemical assay the values were controls, 103.3; heterozygotes, 20.6; patients, 0.46 and 3.5 nm mg−1 h−1. Using both methods it was possible to identify two certain FDPase heterozygotes and three non‐carriers in the family of one of the probands. The radiochemical method was found to be more effective in differentiating heterozygotes from controls than the spectrophotometric method. However, either technique may be conveniently used for the diagnosis of FDPase deficiency in leukocytes.
Decreased procollagen production in cultured fibroblasts from patients with Lowe's syndrome
Authors: Palmieri M. J. , O'Hara J. , States B. , Segal S.
Published: June 2005

The oculo‐cerebro‐renal syndrome described by Lowe is a catastrophic disease in children characterized by progressive eye, central nervous system and kidney degeneration. We determined procollagen production in cultured skin fibroblasts originating from patients with Lowe's syndrome as well as normal individuals after incubation of cells with [14C]proline for 1, 4 and 20 h. Using [14C]hydroxyproline formation, in relation to cell protein or DNA, as an index of procollagen production, we found that cultured cells from patients synthesized collagenous protein at a substantially reduced level. This decrease in synthesis in cultured fibroblasts from patients could not be accounted for by differences in the specific radioactivity of the free intracellular proline; moreover, it could not be attributed to differences in the kinetics of growth between normal and affected cell lines. The degree of hydroxylation of proline residues in collagen was the same in both normal and affected cells.
Plasma lipids and lipoproteins of a patient with cholesteryl ester storage disease
Authors: Kostner G. M. , Hadorn B. , Roscher A. , Zechner R.
Published: June 2005

The plasma lipids, lipoproteins and lipolytic enzymes of a patient suffering from cholesterol ester storage disease were investigated and followed over a time period of 3 years. The patient was hypertriglyceridacmic and cholesterolaemic and exhibited very low levels of high density lipoproteins. These lipoproteins consisted almost exclusively of the HDL‐subfraction‐3. Apolipoprotein‐B was elevated and apoAI and AII were grossly reduced. The activity of lipoprotein lipase was normal, but hepatic lipase values were increased. Lecithin : cholesterol acyltransferase was in the upper normal range. The corresponding lipoprotein and enzyme values of one brother were within normal limits but some components measured in the plasma of the father were abnormal. It is speculated that the low plasma HDL levels in this disease may be a consequence of increased hepatic lipase activity in addition to a derangement in the reverse cholesterol flow.
Persistent succinylacetone excretion after liver transplantation in a patient with hereditary tyrosinaemia type I
Authors: Tuchman M. , Freese D. K. , Sharp H. L. , Whitley C. B. , Ramnaraine M. L. , Ulstrom R. A. , Najarian J. S. , Ascher N. , Buist N. R. M. , Terry A. B.
Published: June 2005

A liver transplant was performed on a 4‐year‐old female in liver failure caused by hereditary tyrosinaemia, with hepatocellular carcinoma following a negative evaluation for metastases. However, serum alpha‐fetoprotein levels never returned to normal after the surgery. Urinary succinylacetone (SA) was detected in her urine prior to transplantation despite strict adherence to a low‐tyrosine diet. Other patients with severe liver disease awaiting liver transplantation do not excrete SA in the urine. She continued to excrete SA during the postoperative period despite normal liver functions. Oral tyrosine loading resulted in significant elevation of SA excretion. Possible explanations for this observation and clinical and therapeutic relevance are discussed.
The glasgow register of congenital anomalies 1972–88: A critical review
Authors: Stone D. H.
Published: June 2005

Since 1972, the Glasgow Register of Congenital Anomalies has collected population‐based data on all anatomical, metabolic and genetic congenital anomalies. Multiple sources of ascertainment, with no time limit for registration, are used. Its objectives are the detection of epidemics, the calculation of prevalence rates, the epidemiological investigation of malformations and the study of cohorts of survivors. A review of the achievements of the Register to date suggests that these objectives have only partly been fulfilled, though a number of recent measures, including the association of the Register with the multi‐centre European Registry (EUROCAT), have improved its future prospects. Previously unpublished data on cystic fibrosis and phenylketonuria are presented indicating that the prevalence rates of these disorders are stable and comparable to those of other centres, while the prevalence of hypothyroidism appears to have risen slightly since 1982.
Transient neonatal tyrosinaemia
Authors: Rice D. N. , Houston I. B. , Lyon I. C. T. , Macarthur B. A. , Mullins P. R. , Veale A. M. O. , Guthrie R.
Published: June 2005

Children who had presented with transient neonatal tyrosinaemia (TNT) were compared with a group of unaffected controls at 7–9 years of age. A comprehensive psychometric assessment revealed significant differences between the groups in adaptive behaviour, psycholinguistic abilities, and speed of learning. In nearly all components of the tests used, higher levels of TNT were associated with lower levels of performance. This study demonstrates that TNT, a condition commonly regarded as benign in the short term, has long‐term effects which may be detrimental to the child in school.
Comparison between the formation and the oxidation of dicarboxylylcarnitine esters in rat liver and skeletal muscle: Possible implications for human inborn disorders of mitochondrialβ‐oxidation
Authors: Vamecq J. , Draye J. ‐P.
Published: June 2005

The activity of dicarboxylyl‐CoA synthetase previously reported in rat liver was detected, in the presence of added detergents, in rat skeletal muscle. In both tissues, carnitine dicarboxylyltransferase activities were recorded but their substrate chain length specificity was, however, different. In rat skeletal muscle, but not liver, a carnitine‐dependent oxidation by intact mitochondria of dodecanedioyl‐CoA was easily detected by the spectrophotometric measurement of the substrate‐dependent ferricyanide reduction.

The implications of the present data for the pathogenesis of disorders with excess urine dicarboxylylcarnitine esters are discussed.
Trimethylaminuria: The detection of carriers using a trimethylamine load test
Authors: Al‐Waiz M. , Ayesh R. , Mitchell S. C. , Idle J. R. , Smith R. L.
Published: June 2005

A method potentially of value for investigating putative heterozygotes or carriers of trimethylaminuria by using a single oral dose of trimethylamine (TMA) is described. For healthy volunteers under normal dietary condition and following oral challenge with 300 mg and 600 mg TMA‐base, over 90% of the urinary TMA was excreted in the form of TMA (93.6 ± 1.6%). However, at a dose level of 900 mg TMA‐base, there was clear evidence of saturation of theN‐oxidation reaction as urinary TMA excretion declined to 77.2% (range 74.8–78.9) of the total dose of TMA. By contrast, in pedigree studies based upon propositi with trimethylaminuria, several parents were identified who showed clear evidence of saturation of theN‐oxidation of TMA at the 600 mg TMA‐base dose level, but not at 300 mg TMA‐base or under normal dietary condition. In these individuals, the proportion of urinary TMA as trimethylamineN‐oxide (TMAO) declined to (77.3 ± 1.7%). Accordingly we propose that the oral administration of 600 mg TMA‐base and the analysis of the following 0–8‐h urine collection may be useful for the investigation of possible carriers of trimethylaminuria.
Fibroblast α‐galactosidase a activity for identification of Fabry's disease heterozygotes
Authors: Fensom A. H. , Benson P. F. , Grant A. Ronayne , Jacobs L.
Published: June 2005

The identification of female carriers of Fabry's disease is important for genetic counselling since prenatal diagnosis of affected fetuses is possible. The activities of either total α‐galactosidase or α‐galactosidase A in cultured fibroblasts were similar in Fabry carriers and controls and cannot therefore be used for carrier detection. Better discrimination between carriers and controls was found when total α‐galactosidase activity was expressed as a ratio to β‐galactosidase activity, but overlap still occurred. However, there was complete discrimination between the ratio of α‐galactosidase A to β‐galactosidase in cultured fibroblasts from five carriers of Fabry's disease and either 11 controls, seven hemizygote affected males or two of their female relatives.
Brain disorders in relation to biochemical lesions
Authors: Wilson J.
Published: June 2005

Conclusion

The paediatric neurologist confronted with an array of named and unnamed heredo‐degenerative disorders, as yet undefined biochemically, is continually frustrated by the therapeutic nihilism and by genetic counselling based on a statistical estimate of risk. Regrettably, clinical observation has provided few clues so far with which to direct research, but since further technical innovation is unlikely to provide helpful answers unless the appropriate questions are asked, it is essential that we go on trying to formulate proper questions.
Neutropenia and impaired neutrophil function in glycogenosis type Ib
Authors: Di Rocco M. , Borrone C. , Dallegri F. , Frumento G. , Patrone F.
Published: June 2005

The impairment of different neutrophil functions has recently been reported in some patients with glycogenosis Ib and neutropenia. However, no satisfactory explanation for these findings has so far been supplied. In order to investigate this problem, we have studied neutrophil functions (random locomotion and chemotaxis, O2− release, [1‐14C]glucose oxidation and cellular cytotoxicity) in two further patients with glycogenosis Ib and neutropenia. The results show that neutrophil dysfunctions related to the involvement of both hexose monophosphate shunt and anaerobic glycolysis were variable. The heterogeneity of neutrophil functional impairment in glycogenosis Ib and their possible relationship with the basic metabolic defect of the disease are discussed.
The pH of mitochondria of fibroblasts from a hyperornithinaemia, hyperammonaemia, homocitrullinuria‐syndrome patient
Authors: Metoki K. , Hommes F. A.
Published: June 2005

The intracellular pH of control fibroblasts and of fibroblasts of a HHH‐syndrome patient have been determined. Values of 6.94±0.15 and 7.05±0.14 for control and patient fibroblasts, respectively, were found. By means of analyses of malate in the cytosolic and particulate fractions of the fibroblasts the differences in pH between these two cellular compartments were estimated to be 1.34±0.12 and 1.38±0.18 for control and patient, respectively. Neither difference was statistically significant. The decrease in the rate of ornithine uptake by mitochondria of the patient's fibroblast is therefore not due to an increased intramitochondrial pH.
Immune functions in methylmalonicaciduria
Authors: Church J. A. , Koch R. , Shaw K. N. F. , Nye C. A. , Donnell G. N.
Published: June 2005

A variety of phagocytic cell and lymphocyte assays were employed to evaluate the immune status of four patients with methylmalonicaciduria. One patient had a depressed absolute granulocyte count and two patients had depressed neutrophil and monocyte chemotactic responses. All subjects had normal neutrophil phagocytic and bactericidal activities. One patient had a decreased T‐cell number; blastogenic responses to phytohaemagglutinin and pokeweed mitogen were normal in all subjects. B lymphocyte measurements were variably abnormal; two children had decreased B‐cell numbers; two had marginally decreased IgG levels; a third had an undetectable rubella titre; and two had elevated serum IgE concentrations.In vitro exposure of normal cells to methylmalonic acid concentrations up to 50mg/100 ml did not affect chemotactic or lymphoproliferative responses.

In conclusion, although B‐cell function may be affected, no consistent abnormality of lymphocyte or phagocytic cell functions could be attributed to the metabolic disorder.
Congenital dislocation of the hip: A possible inborn error of collagen metabolism
Authors: Skirving A. P. , Sims T. J. , Bailey A. J.
Published: June 2005

Significant changes in the type of collagen, the fibril diameter and the nature of the crosslinks have been demonstrated in the joint capsules of subjects with congenital displacement of the hip (CDH). These changes are probably tissue specific since no detectable change could be observed in the skin of these subjects compared to controls. These preliminary biochemical studies clearly demonstrate that CDH involves an error in collagen metabolism.
Serum and hair zinc as predictors of clinical symptoms in acrodermatitis enteropathica
Authors: Anttila P. , Simell O. , Salmela S. , Vuori E.
Published: June 2005

Hair‐ and serum‐zinc concentrations were measured in six patients with acrodermatitis enteropathica before and sequentially after cessation of zinc supplementation; supplementation was restarted when symptoms appeared. Serum zinc correlated accurately with zinc dosage and was lowest when symptoms of deficiency appeared. Hair zinc was initially age‐ and body size‐related and was minimally influenced by the supplementation break. Adult patients had continuously normal concentrations. In paediatric patients hair zinc was low. Their serum concentrations should probably be maintained slightly above or at the upper limit of reference values for prolonged periods for normalization of hair and perhaps tissue zinc contents.
A sensitive semi‐automated kinetic assay of α‐D‐glucosidase for the prenatal diagnosis of type 2 glycogenosis (Pompe's disease)
Authors: Blau K.
Published: June 2005

Prenatal diagnosis of type 2 glycogenosis (Pompe's disease) has been done on cultured amniotic fluid cells, using a semi‐automated fluorimetric kinetic assay for α‐D‐glucosidase with 4‐methylumbelliferyl‐α‐D‐glucoside as substrate. The activity of the enzyme was related to that ofβ‐D‐galactosidase, and found to be absent in cells from an affected fetus. The diagnosis was confirmed in fetal liver, where the same assay was used to show absence ofα‐D‐glucosidase activity with normalβ‐D‐galactosidase activity, and where increased glycogen deposition was demonstrated histologically. This type of assay is generally applicable to lysosomal enzymes, and to other fluorigenic enzyme reactions.
Deranged isoleucine metabolism during ketotic attacks in patients with methylmalonic acidaemia
Authors: Duran M. , Bruinvis L. , Ketting D. , Wadman S. K.
Published: June 2005

Two patients with methylmalonic acidaemia due to methylmalonyl‐CoA mutase deficiency were studied for several years. Both exhibited at least two attacks of severe ketoacidosis, during which they excreted, in addition to methylmalonic acid, a number of abnormal compounds: 3‐hydroxypropionic acid, 2‐methyl‐3‐hydroxybutyric acid, 3‐hydroxy‐n‐valeric acid, 3‐oxo‐n‐valeric acid, 2‐methyl‐3‐oxobutyric acid, citraconic acid andN‐tiglylglycine. These compounds represent partly intermediary metabolites from the isoleucine degradation pathway and partly secondary metabolites of propionyl‐CoA and tiglyl‐CoA.
A new patient with dicarboxylic aciduria suggestive of medium‐chain acyl‐CoA dehydrogenase deficiency presenting as Reye's syndrome
Authors: Del Valle J. A. , Garcia M. J. , Merinero B. , Pérez‐Cerdá C. , Roman F. , Jimenez A. , Ugarte M. , Martínez‐Pardo M. , Ludeña C. , Camarero C. , del Olmo R. , Duran M. , Wadman S. K.
Published: June 2005

A new patient with medium‐chain dicarboxylic aciduria and suberyl glycinuria during an attack of acute illness is reported. When, inadvertently he was given medium‐chain triglycerides for 2 days, the excretion of abnormal metabolites of medium‐chain fatty acids increased and hepatomegaly became more pronounced. During remission a low excretion of the metabolites were observed. After 16 h of fasting hypoglycaemia was accompanied by an increase of urinary dicarboxylic acids and ψ‐hydroxyacids similar to that found on admission. Interestingly this urinary organic acid pattern persisted 8 h after intravenous administration of glucose. In a blood sample obtained after 16 h of fasting there was hypoketonaemia and increased levels of total free fatty acids, octanoic, decanoic andcis‐4‐decenoic acids. These biochemical data suggest the existence of a deficiency at the level of medium‐chain acyl‐CoA dehydrogenase.
Dihydropteridine reductase deficiency: Non‐response to oral tetrahydrobiopterin load test
Authors: Lipson A. , Yu J. , O'Halloran M. , Potter M. , Wilken B.
Published: June 2005

In a child with dihydropteridine reductase deficiency (McKusick 26163) none of four separate oral tetrahydrobiopterin loading tests resulted in a decrease of the serum phenylalanine concentration. This test cannot be recommended for screening hyperphenylalaninaemic patients for dihydropteridine reductase deficiency.
Paired comparisons between early treated PKU children and their matched sibling controls on intelligence and school achievement test results at eight years of age
Authors: Koch R. , Azen C. , Friedman E. G. , Williamson M. L. ,   Writing Committee for the PKU Collaborative Study
Published: June 2005

Early‐treated PKU children were compared to their matched non‐PKU sibling controls on Wechsler Intelligence Scale for Children (WISC) and Wide Range Achievement Test (WRAT) results at age 8. Fifty‐five PKU children had mean WISC Full Scale IQ score of 100, in comparison to a mean of 107 for their matched sibling controls (p=0.001). Treatment parameters significantly correlated with sibling‐PKU IQ score differences included maximum diagnostic phe level (r=0.244,p=0.036) and phe levels at age 6 (r=0.329,p=0.007) and at age 8 (r=0.489,p<0.0005). Fifty PKU subjects scored significantly lower than their matched sibling controls on standard scores of the WRAT Reading (102 vs. 107,p=0.016) and Arithmetic (96 vs, 101,p=0.006) subtests, and lower, but not significantly so, in Spelling (100 vs. 103,p=0.145). When the sample was grouped according to diet status at age 8, on‐diet PKUs scored at or above the level achieved by their siblings on all three scales of the WISC and all three WRAT subtests, whereas the off‐diet group scored from 7 to 13 points below their siblings on all measures.

These results suggest that PKU children should restrict phe intake at least through their school years.
Metallothionein — Aspects related to copper and zinc metabolism
Authors: Cousins R. J.
Published: June 2005

Metallothionein is a cysteine‐rich, low molecular weight protein that binds zinc, copper and cadmium. It is inducible in liver, kidney and intestine by glucocorticoids, changes in the dietary zinc supply, acute administration of various metals, food restriction, infection, stress and endotoxin treatment. Regulation of synthesis involves altered gene expression. The protein is fairly rapidly degraded when zinc is the primary metal species bound, but the degradation rate is diminished when cadmium or copper are bound as well. The net result of metallothionein production seems to be accumulation of bound metal and/or intracellular metal redistribution. The accumulation of copper in various tissues of individuals with Menkes' and Wilson's diseases may be related to altered metallothionein turnover. The physiological function is not clear, but the response of metallothionein to hormonal stimuli is suggestive of an important role in cellular metabolism.
Hudson memorial lecture: Wilson's disease: Genetics and biochemistry—their relevance to therapy
Authors: Walshe J. M.
Published: June 2005

Wilson's disease is an inherited metabolic disorder affecting children, adolescents and young adults. Before puberty the initial signs and symptoms are almost always related to liver damage, with or without haemolysis. After puberty neurological signs become increasingly prominent, always involving the motor centres, sometimes personality, never the sensory nervous system. The most characteristic physical sign is the Kayser Fleischer corneal pigment ring resulting from deposition of copper in Descemet's membrane.

The primary genetic defect is not known but the disease appears to result from a failure, by the hepatocytes, to excrete copper via the bile. As a result this metal accumulates first in the liver then, when this organ is saturated, in the brain, the corneae, and to a lesser extent the kidneys. Once present in excess in the tissues copper poisons various enzyme systems leading to cellular damage and death. At present there is no satisfactory explanation for the pleomorphic nature of the disease much less of the often gross assymetry of the lesions in the brain.

Treatment entails the establishment of a negative copper balance until the abnormal body stores of the metal have been removed. Thereafter the patient must be kept in balance for life. There are two main drugs available for this purpose, penicillamine and triethylene tetramine (Trientine). Both will achieve biochemical and clinical reversal of the disease. Penicillamine can give rise to a wide range of toxic reactions, mostly on an immunological basis; it is therefore essential to monitor the blood count and renal function regularly. Less is known at present of the potential of Trientine to induce unwanted side effects.

Wilson's disease is characterized by recessive inheritance. It can be diagnosed in the presymptomatic stage by finding typical abnormalities of copper metabolism. All families should be screened and, where appropriate, prophylactic treatment started, thus aborting the clinical evolution of the disease.
Iron and haemochromatosis
Authors: Worwood M.
Published: June 2005

There have recently been considerable advances in the understanding of the inheritance of idiopathic haemochromatosis (McKusick 23520). The disorder is determined by a locus closely linked to the HLA loci on the short arm of chromosome 6. There is a recessive mode of transmission. The gene frequency may be as high as 0.05 in some parts of the world. HLA typing makes it possible to identify family members who are homozygous for idiopathic haemochromatosis and measurement of transferrin saturation and serum ferritin concentration will identify those with iron overload. Treatment is by regular phlebotomy. Few advances have been made in the 50 years in the understanding of the abnormality which permits the increased absorption of iron and which causes the iron overload.
The role of peroxisomes in mammalian cellular metabolism
Authors: Lazarow P. B.
Published: June 2005

Peroxisomes, which are widely distributed in mammalian tissues, carry out several important functions in cellular metabolism. Production of alkylglycerol‐3‐phosphate, a key intermediate in the synthesis of plasmalogens and other ether lipids, occurs in the peroxisome. A fatty acid β‐oxidation system with significant differences from mitochondrial β‐oxidation is also found in the peroxisomes; the acetyl‐CoA produced is used for synthetic reactions. This pathway has a particularly important physiological role in the oxidation of very long chain fatty acids and the side chain of cholesterol. Peroxisomes also possess a number of oxidases that produce H2O2 which is decomposed by peroxisomal catalase. The function of this peroxisomal respiratory pathway is disposal of excess reducing equivalents, protection of the cell against H2O2 and possibly a role in thermogenesis in brown adipose tissue. Other peroxisomal functions include a role in gluconeogenesis and in purine and polyamine catabolism. Some enzymes of peroxisomes can be induced by dietary, hormonal and other physiological changes. The entire organelle proliferates under certain of these conditions.
Biogenesis of mitochondria and genetics of mitochondrial defects
Authors: Kroon A. M. , Van den Bogert C.
Published: June 2005

Mitochondria are formed by the concerted action of two genetic systems: the nucleocytoplasmic system and the intrinsic mitochondrial system. The genetic contribution of the mitochondria is modest because the genetic potential of mtDNA of mammals is restricted to the equivalent of about 16 000 base pairs. For various animals and man the complete base sequence of mtDNA is known and all possible polypeptide genes have now been assigned to subunits of the respiratory enzymes. The mtDNA sequences are not present on the nuclear genome.

From a genetic point of view it is important that the inheritance of mtDNA is strictly maternal. Mutations of mtDNA primarily lead to impairments of energy metabolism. In view of the indispensability of oxidative phosphorylation for obligatory aerobic organisms, such mutations should be lethal. However, there are various inborn errors of metabolism with tissue‐specific manifestations, which are maternally inherited. The question discussed is whether these diseases can be explained on the basis of mutations of mitochondrial gene products. Tissue specificity poses a special problem, since it is not very attractive to assume that there is a heterogenous population of mtDNA molecules in the fertilized egg. Therefore, one should rather think in terms of a double mutational event, one tissue‐specific cytoplasmic and the other general mitochondrial. These mutations only give rise to metabolic disturbances if they are expressed together in the same cell.
Defects of fatty acid oxidation in skeletal muscle
Authors: Turnbull D. M. , Bartlett K. , Watmough N. J. , Shepherd I. M. , Sherratt H. S. A.
Published: June 2005

Fatty acids are important substrates for resting and exercising skeletal muscle. Defects of fatty acid oxidation result in muscle pain and weakness, and there is often lipid accumulation in muscle fibres. Only a few of the several possible enzyme defects have been found and some of these have responded to therapy. Some techniques for the investigation of fatty acid oxidation are outlined.
Mitochondrial myopathies
Authors: DiMauro S. , Bonilla E. , Zeviani M. , Servidei S. , DeVivo D. C. , Schon E. A.
Published: June 2005

The mitochondrial myopathies or encephalomyopathies with known biochemical defects can be divided into 5 groups: (1) defects of mitochondrial transport, such as CPT deficiency or carnitine deficiencies; (2) defects of substrate utilization, such as PDHC deficiency or defects of β‐oxidation; (3) defects of the Krebs cycle, such as fumarase deficiency; (4) defects of oxidation‐phosphorylation coupling, such as Luft disease, and (5) defects of the respiratory chain. These disorders are reviewed, with particular emphasis on the defects of the respiratory chain. Defects of complex I, III and IV show remarkable clinical and biochemical heterogeneity. All 3 complexes contain some subunits encoded by mtDNA and others encoded by nuclear DNA. At least some of the cytoplasmically made subunits appear to be tissue specific and may be developmentally regulated, thus explaining the genetic heterogeneity of these disorders.
Magnetic resonance spectroscopy in the recognition of metabolic disease
Authors: Griffiths R. D. , Edwards R. H. T.
Published: June 2005

Magnetic resonance (MR) is rapidly entering many fields of clinical medicine following a long history as a powerful tool in physics and chemistry. The non‐invasive and non‐destructive property of this technique has enabled the chemical shift in higher magnetic fields to be exploited to identify and quantitate metabolites in bothin vitroandin vivoanalysis. High resolution proton spectroscopy of body fluids has been shown to be complementary with established analytical techniques, while the development of whole body large bore magnets is enabling both the study of structure and metabolism in humansin vivo. Phosphorus MR spectroscopy has provided a method of monitoring ATP production and utilisationin situin both perfused preparation and intact tissue. In human muscle it has been possible to test established theories of tissue energy metabolism. It provides a unique method with which to evaluate the state of tissue oxidative metabolism. The opportunities afforded by other nuclei are being studied, but the low sensitivity of the MR technique forces limitations. Recent technical advances in tissue localization have as yet only been applied in a limited way. The use of MR in metabolic disease will be considered with specific reference to disorders of skeletal muscle metabolism.
The inborn errors of mitochondrial fatty acid oxidation
Authors: Vianey‐Liaud C. , Divry P. , Gregersen N. , Mathieu M.
Published: June 2005

To date, seven inborn errors of mitochondrial fatty acid oxidation have been identified. A total of about 100 patients in the world have been reported. Clinically the β‐oxidation defects are more often characterized by episodic hypoglycaemia leading to a coma mimicking Reye's syndrome. The hypoglycaemia is non‐ketotic since the synthesis of ketone bodies is deficient. Periods of decompensation occur when carbohydrate supply is poor, e.g. prolonged fasting, vomiting, or increased caloric requirements, as and when lipid stores are used. Defects in β‐oxidation have also been reported to be one cause of sudden infant death syndrome. The diagnosis of these inborn errors is by biochemical investigation since where symptoms suggest such a defect, the precise aetiology cannot be assessed. The biochemical diagnosis is based firstly on identification of abnormal plasma and of urinary metabolites during acute attacks. Derivatives of the ω‐oxidation and ω‐1‐oxidation of medium chain fatty acids have been identified, as well as acylglycine and acylcarnitine conjugates. These metabolites are nearly always absent when patients are in good clinical condition. Secondly, the diagnosis must be based on the identification of the enzymatic defects: this involves global assays which allow a localization of the ‘level’ of the defect (i.e. the oxidation of long, medium or short chain fatty acids) and specific measurement of enzyme activities (acyl‐CoA dehydrogenases and electron carriers: ETF and ETF‐DH). The diagnosis of these disorders is of prime importance because of the severity of the clinical symptoms. These can be prevented, in some cases, by an appropriate diet (a high carbohydrate, low fat diet, sometimes supplemented withl‐carnitine). In other cases, genetic counselling can be offered.
Protein‐bound plasma homocyst(e)ine and identification of heterozygotes for cystathionine‐synthase deficiency
Authors: Sartorio R. , Carrozzo R. , Corbo L. , Andria G.
Published: June 2005

We measured protein‐bound plasma homocyst(e)ine in 15 normal adult subjects and nine heterozygotes for homocystinuria due to cystathionine β‐synthase deficiency. The mean (±SD) concentrations obtained in the two groups of subjects were 4.35±1.50 and 9.16±3.40 µmoll−1, respectively. The mean values were significantly different, although the levels of three heterozygotes overlapped those of the control range. This method allows preliminary screening of the heterozygotes for homocystinuria and can be carried out by laboratories that have only facilities for amino acid analysis.
Family studies of the Lesch‐Nyhan syndrome: the use of a restriction fragment length polymorphism (RFLP) closely linked to the disease gene for carrier state and prenatal diagnosis
Authors: Gibbs D. A. , Headhouse‐Benson C. M. , Watts R. W. E.
Published: June 2005

We have investigated the usefulness of a full‐length cDNA probe for the hypoxanthine phosphoribosyltransferase, HPRT gene in the diagnosis of the carrier state for the Lesch‐Nyhan syndrome in 13 families. The products of DNA digestion by 21 different restriction enzymes were examined by Southern analysis. The only useful polymorphism detected was a three allele polymorphism withBam HI; others were found withMsp I andHind III but they were not linked to the disease. None of the boys with the Lesch‐Nyhan syndrome had a unique polymorphism and therefore a detectable gene deletion or other major structural alteration. A DNA polymorphism capable of giving additional diagnostic information with respect to carrier status was present in 8 of the 13 families, but not for all of the family members at risk. The cDNA probe and restriction enzyme analysis gave anunequivocal diagnosis to 20 women out of 28 who might have been carriers and for whom it would not have been available on the basis of pedigree analysis and biochemical tests alone. If a linked polymorphism is to be useful for carrier detection it must be present in only one of the mother's X‐chromosomes (i.e. the mother must carry a different allele on each X‐chromosome). Although this polymorphism is detected by an HPRT probe it is not at the site of the specific gene lesion. In spite of considerable genetic heterogeneity, most cases of the Lesch‐Nyhan syndrome appear to be due to either single base substitutions or small deletions which are not detectable by Southern analysis. None of the propositi in these families was due to a new mutation arising in the maternal germ line. One family was identified in which the evidence was compatible with a mutation having arisen in the X‐chromosome which the mother of the propositus inherited from her father, and in another family the mutation arose in the maternal grandmother. A case illustrating the application of this restriction fragment length polymorphism to the first trimester prenatal diagnosis of the Lesch‐Nyhan syndrome is also reported. This study illustrates the limitations as well as the value of using a linked DNA polymorphism for carrier state diagnosis in X‐linked diseases.
β‐mannosidosis: Prenatal detection of caprine allantoic fluid oligosaccharides with thin layer, gel permeation and high performance liquid chromatography
Authors: Dahl D. L. , Warren C. D. , Rathke E. J. S. , Jones M. Z.
Published: June 2005

In the goat, β‐mannosidosis can be diagnosed before birth from the concentrations of oligosaccharides in allantoic fluid.
Outcome of pregnancy in the rat with mild hyperphenylalaninaemia and hypertyrosinaemia: Implications for the management of “human maternal PKU”
Authors: Lewis S. A. , Lyon I. C. T. , Elliott R. B.
Published: June 2005

In attempting to determine the effects of mildly elevated maternal phenylalanine (Phe) blood levels on the developing fetal rat brain, a dietary supplement of Phe was given, under taste cover of Aspartame. Phe and tyrosine (Tyr) levels were mildly elevated throughout pregnancy without evidence of malnutrition. Mild hyperphenylalaninaemia with concurrent hypertyrosinaemia induced in rats prior to conception resulted in microcephaly and lasting behavioural problems in the offspring, specifically hyperactivity and learning difficulties. Dams fed Tyr to produce Tyr levels equivalent to the Phe‐fed animals showed only the learning difficulties among the offspring.

α‐Methyl Phe, a Phe hydroxylase inhibitor, fed in conjunction with Phe, at the level relevant to these experiments, resulted in raised Tyr levels and does not provide a better method of determining whether mildly elevated maternal Phe levels alone, or Phe and Tyr in combination, cause the abnormality found in the offspring of Phe‐supplemented dams.

Therapeutic addition of Tyr to diets of mothers with even mild hyperphenylalaninaemia should be approached with caution as mild co‐elevation of Phe and Tyr in the fetus may be harmful.

In the face of such a possible therapeutic dilemma alternatives, such as dietary additions of other essential amino acids to limit fetal brain damage, need to be explored.
Comparative column chromatographic estimations of phenylalanine in plasma, whole blood, native and paper‐dried capillary blood of healthy children and adults, and patients with hyperphenylalaninaemia
Authors: Becker K. , Harenz J. , Kalle N. , Hommel G. , Behbehani A. W.
Published: June 2005

The concentration of phenylalanine in plasma, whole venous and capillary blood, and paper‐dried blood of 75 probands (25 healthy adults, 27 healthy children, and 23 patients with hyperphenylalaninaemia) were measured by use of a sensitive short column chromatography method. The comparison of the values in each group of probands by several statistic methods showed an excellent correlation of the phenylalanine concentration in paper‐dried whole blood to those measured in venous plasma. Evaluation of the analytical method revealed a high sensitivity and accuracy by use of a sample volume of 50 µl. We would therefore suggest that the estimation of phenylalanine for the diagnosis and therapy control in hyperphenylalanine is as accurate in paper‐dried blood as in venous plasma and would simplify sampling for the patients as well as enhance the diagnosis and therapy control in hyperphenylalaninaemia.