Vitiligo is not caused by mutations in GTP-cyclohydrolase I gene.

GTP-cyclohydrolase I (GTP-CH I) is the initial and rate-limiting enzyme in the synthesis of tetrahydrobiopterin, which regulates melanin biosynthesis. GTP-CH I is therefore a candidate gene for vitiligo. We have carried out DNA sequencing of all six exons and the promoter region of this gene, comprising 1759 base pairs, in 25 nonsyndromic vitiligo patients. However, contrary to an earlier report in which mutations were found in syndromic patients (vitiligo with dopa-responsive dystonia) belonging to two unrelated families, no mutation in the GTP-CH I gene was found.