Minifascicular neuropathy: a new concept of the human disease caused by desert hedgehog gene mutation.

We recently found a patient with 46,XY partial gonadal dysgenesis who presented with polyneuropathy. Sural nerve pathology revealed peculiar findings characterized by extensive minifascicular formation and with a decreased density of myelinated fibers. We found in the patient, a homozygous missense mutation at the initiating codon in exon 1 of the desert hedgehog (DHH) gene, which predicts a failure of translation of the gene. These data demonstrate that DHH is a key molecule in both male gonadal differentiation and perineurial formation in peripheral nerves.