Clinical and molecular studies of brachydactyly type D.

We report on the clinical manifestations in six affected individuals from a four-generation family that segregates brachydactyly type D (BDD). All affected individuals have either bilateral and symmetric or unilateral first distal phalangeal hypoplasia. Metacarpal-phalangeal profiles show that some affected individuals also have a more generalized involvement of the apical skeleton. However, other than first distal phalangeal hypoplasia, there is no consistent pattern of associated skeletal involvement. Linkage analyses were preformed between the BDD phenotype in this family and six loci known to contain genes involved in apical skeletal patterning. No statistically significant linkage was detected.