Unusual presentation of Kelley-Seegmiller syndrome.
Female carriers of hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency have somatic cell mosaicism of HPRT activity and are healthy. We report a 50-year-old woman without gout or nephrolithiasis. She was never on allopurinol. Normal serum uric acid concentrations, increased plasma hypoxanthine, and xanthine were found. HPRT activity in erythrocytes was surprisingly low: at 8.6 nmol h(-1) mg (-1) haemoglobin. Mutation analysis revealed a heterozygous HPRT gene mutation, c.215A > G (p.Tyr72Cys). Assessment of X-inactivation ratio has shown that > 75% of the active X-chromosome bears the mutant allele and could explain these unusual, previously undescribed findings.
Sebesta
I
I
Institute of Inherited Metabolic Disorders, Charles University, Prague, Czech Republic. isebes@lf1.cuni.cz
Stiburková
B
B
Dvorakova
L
L
Hrebicek
M
M
Minks
J
J
Stolnaja
L
L
Vernerova
Z
Z
Rychlik
I
I
D000328:Adult; D000483:Alleles; D005260:Female; D006579:Heterozygote; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D007926:Lesch-Nyhan Syndrome / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D011687:Purines / Q000097:blood; D013577:Syndrome; D049951:X Chromosome Inactivation
D011687:Purines; D007041:Hypoxanthine Phosphoribosyltransferase; C030985:purine