We describe a patient with 46,XY partial gonadal dysgenesis (PGD) who presented with polyneuropathy. Sural nerve pathology revealed peculiar findings characterized by extensive minifascicular formation within the endoneurium and with a decreased density of myelinated fibers. We found, in the patient, a homozygous missense mutation (ATG-->ACG) at the initiating codon in exon 1 of the desert hedgehog (DHH) gene, which predicts a failure of translation of the gene. The same heterozygous mutation was found in the patient's father. This is the first report of a human DHH gene mutation, and the findings demonstrate that mutation of the DHH gene may cause 46, XY PGD associated with minifascicular neuropathy.