BACKGROUND: @entity8324 @entity1 may be classified into several subgroups based on the urinary phenotype of heterozygotes. However, the relative risk for @entity1790 and the prevalence of @entity32372 mutations in these subgroups are unknown. METHODS: Urinary @entity1434 excretion, age at onset of @entity1790 and nature of @entity32372 mutations were assessed prospectively in 23 @entity8324 @entity1 identified primarily through the Quebec Newborn Screening Program. Probands were classified as to @entity8324 subtype on the basis of parental urinary @entity1434 excretion. RESULTS: For classical Type I/I @entity8324 , both parents excrete @entity1434 in the normal range and probands carry two mutations of the @entity32372 gene in nearly every case. Between ages 1 to 7 years, mean @entity1434 excretion was high (4566 +/- 480 microns @entity1434 /g @entity1011 ) and exceeded the theoretic threshold for solubility on 70% of visits. Four of eight Type I/I @entity1 began forming stones in the first decade. Type I/III @entity1 (N = 12) excreted less @entity1434 (1544 +/- 163 mumol @entity1434 /g @entity1011 ), exceeded the threshold of urinary @entity1434 solubility less frequently (22% of visits) and had no @entity1790 in the first decade; one formed a stone at age 16 years. Only one @entity32372 mutation was identified in this group. Two @entity43597 @entity8324 @entity1 were identified. In these families, the same level of relatively high excretion (> 600 mumol @entity1434 /g @entity1011 ) was noted in two or three generations, but no @entity32372 mutations were identified. CONCLUSIONS: Classical recessive Type I/I @entity8324 is genetically and phenotypically distinct from the other subtypes (Type I/III and @entity43597 ) identified in our population.

XXXX subtype and the risk of @entity1790 .

@entity1 :: ('9606', 'Species') :: ['children', 'patients'] @entity43597 :: ('MESH:C536631', 'Disease') :: ['Type II/N'] @entity8324 :: ('MESH:D003555', 'Disease') :: ['cystinuria', 'Cystinuria'] @entity32372 :: ('6519', 'Gene') :: ['SLC3A1'] @entity1790 :: ('MESH:D053040', 'Disease') :: ['nephrolithiasis'] @entity1434 :: ('MESH:D003553', 'Chemical') :: ['cystine'] @entity1011 :: ('MESH:D003404', 'Chemical') :: ['creatinine']
@entity8324 :: (MESH:D003555,Disease) :: ['Cystinuria']
