Brachydactyly, Mononen Type

Mononen et al. (1992) suggested X-linked dominant inheritance for a syndrome that had as its most striking feature short, abducted thumbs and markedly short and abducted great toes. Variable mild short stature and mild bowleg with proximal overgrowth of the fibula were also features. The x-rays of the hands and feet showed short first metacarpals and first metatarsals, absent distal phalanges of the index fingers and second toes, and coalescence of the carpal and tarsal bones. Males were similarly affected, whereas females showed phenotypic variation and were generally less severely affected. Two rather extensively affected pedigrees were observed. There was no male-to-male transmission and all daughters of affected males were thought to be affected. Similar changes in the hands and feet have been described without associated changes of skeletal dysplasia (see 112450).