Genotypic characterization of the French cohort of Lesch-Nyhan patients. A) Average diagnosis age of the patient as function of symptoms severity. The median age is represented by the thick black line: HRH: HGprt-related Hyperuricemia (Median age 25 years old). HND: HGprt-related hyperuricemia with neuro-muscular dysfunction (Median age 18 years old). LND: full Lesch-Nyhan disease (Median age 3 years old). B) Distribution of mutation types throughout the HPRT1 gene among the three groups of HGprt deficient patients. Black, blue and orange boxes represent mutations in LND, HND and HRH patients, respectively. C) Localization of the mutations on the HPRT1 gene in the French cohort of LN patients. Briefly, mutations were identified by DNA exon and exon-intron junctions sequencing. In yellow boxes are the mutations found in more than one family.