Clinical and biochemical findings of a patient with thanatophoric dysplasia type I: additional finding of dicarboxylic aciduria.

OBJECTIVE: A long-surviving thanatophoric dysplasia type I patient to age of 6 years is presented. RESULTS AND CONCLUSIONS: Molecular studies revealed a heterozygous point mutation, S249C in the fibroblast growth factor receptor 3 gene. Most of the clinical course was similar to previous reports, including hearing loss and acanthosis nigricans. Abnormal urinary excretion of dicarboxylic acids and 3-hydroxydicarboxylic acids was observed. We hypothesize that this was a consequence of the FGFR3 mutation.