Brachydactyly Type E; Brachydactyly Type D

Abstract

In brachydactyly type E (BDE), the 3rd, 4th, and 5th metacarpals and/or metatarsals are short and the most frequently affected. The phalanges may also be involved. There is wide variability in the number of digits affected, even within the same family. The metacarpals make up the knuckles of the hand and normally form a line. A typical clinical sign of BDE can be seen if a fist is made that reveals the shortness of the affected metacarpals. In a subgroup of BDE with mutations in PTHLH, abnormalities of dentition may occur, including oligodontia and delayed eruption of the primary and secondary teeth. Short stature can be an associated feature. In brachydactyly type D (BDD), the distal phalanx of the thumb is shortened to various degrees. The toes are broad. Penetrance is complete in females and incomplete in males. About three-fourths of affected persons, both males and females, express the trait bilaterally. BDD is often a component of BDE.