This report studies a 42-year-old 46,XX patient affected by palmoplantar keratoderma. clinically classified as Huriez syndrome. The patient showed a male phenotype with apparently normal male features including testicular development. Cytogenetic and chromosomal painting analysis excluded the presence of translocation of the Y chromosome. PCR analysis of genomic DNA failed to detect the presence of the testis-determining gene, SRY. The presence of other Y-chromosome genes, known to be involved in testicular maturation and spermatogenesis, has also been analyzed. The data suggest that the sex reversal in this 46,XX male patient is due to a defect on a yet unidentified autosomal or X-linked sex-determining gene. The relationship between the sex reversion and the presence of sclerotylosis is discussed.