Preaxial Deficiency, Postaxial Polydactyly, And Hypospadias

A number sign (#) is used with this entry because of evidence that the phenotype can be caused by mutations in the HOXA13 gene (142959).

Clinical Features

Guttmacher (1993) suggested that a disorder he observed in a father and son and daughter was distinct from the hand-foot-genital (HFG) syndrome (140000) which it resembled in some ways. All 3 individuals were born with preaxial deficiencies of the hands and feet and postaxial polydactyly of the hands. Both the father and the son had glanular hypospadias. Guttmacher (1993) thought the condition could be distinguished from the HFG syndrome by the shortness of the second toes in all 3 affected persons but particularly by the presence of postaxial polydactyly which, he stated, had never been noted in the HFG syndrome.

Molecular Genetics

Because of similarities to the hand-foot-genital syndrome, which is caused by mutations in the HOXA13 gene, Innis et al. (2002) reinvestigated the family reported by Guttmacher (1993) and found a specific HOXA13 missense mutation, gln50 to leu (Q50L; 142959.0005). The mutation had arisen on an allele already carrying a novel 2-bp deletion in the promoter region of the gene. The deletion produced no detectable abnormalities on its own, but may have contributed to the phenotype in the affected individuals, which differed somewhat from that of hand-foot-genital syndrome.