Size reduction associated with brachymesophalangia‐5: A possible selective advantage

Subjects with brachymesophalangia‐5 (the short middle segment trait of the fifth digit) are systematically reduced in the length of the second metacarpal and in stature, by approximately 0.5 standard deviations, in contrast with unaffected individuals or unaffected siblings of affected propositi. There is conclusive evidence for axial and appendicular length reduction in affected individuals, and the smaller body size associated with brachymesophalangia‐5 may confer a selective advantage during growth under conditions of chronic caloric or protein‐calorie malnutrition.