Triphalangeal Thumbs With Brachyectrodactyly

Clinical Features

In 2 seemingly unrelated Mexican kindreds, Carnevale et al. (1980) described an unusual pattern of limb malformations: triphalangeal thumbs and brachydactyly of the index fingers and third toes. In both kindreds, some persons had ectrodactyly of the feet and less often ectrodactyly in the hands. No similar syndrome was found in the literature.

Silengo et al. (1987) reported a sporadic case and another family in which 4 females in 3 generations were affected with considerable variability in expression.

Zenteno et al. (1996) described a new Mexican family with the triphalangeal thumb-brachyectrodactyly syndrome. The 17-year-old proposita showed the classic malformation pattern: triphalangeal thumb, brachysyndactyly in the hands, and ectrodactyly in the feet. Several members of the family had similar malformations, and others presented minor manifestations of the disorder (brachydactyly and nail dysplasia). This was the fourth reported family with the complex and the third of Mexican origin. There was at least one instance of male-to-male transmission.

Inheritance

Silengo et al. (1987) and Zenteno et al. (1996) reported families with triphalangeal thumb-brachyectrodactyly syndrome in an autosomal dominant inheritance pattern.