To analyze the 3beta-hydroxysteroid dehydrogenase (NSDHL) gene in verruciform xanthoma (VX) to elucidate its potential role in the histogenesis of this lesion.DNA was extracted from paraffin-embedded tissue, followed by polymerase chain reaction amplification of exons 4 and 6 of the NSDHL gene. The polymerase chain reaction products were then directly sequenced and analyzed for the presence of somatic mutations.Nine lesions of VX from 8 patients and 3 unrelated normal controls were evaluated.Two of 9 VXs (22%) demonstrated a novel somatic missense mutation in exon 6 of the NSDHL gene. The mutation was not present in the remaining 7 lesions of VX, nonlesional internal controls, and 3 unrelated normal controls. No mutation of exon 4 was found in any case. Mutations of exons 4 and 6 previously identified in CHILD syndrome were not seen in our cases.(1) A novel missense mutation (R199H) in exon 6 of the NSDHL gene was identified in a small subset of sporadic VXs. (2) Known CHILD syndrome mutations in exons 4 and 6 of the NSDHL gene do not contribute to the histogenesis of sporadic VXs.