The molecular control of upper extremity development: Implications for congenital hand anomalies

As the molecular aspects of limb development are being unraveled, more of t he congenital anomalies seen by hand surgeons in the clinical setting will have an identifiable molecular basis. The majority of the data available re garding the molecular development of the upper extremity have come from exp erimental animal studies, specifically the mouse and chicken. These finding s are being discovered by either direct surgical and molecular manipulation of the developing limb or by production of mice deficient in specific gene s. Relatively few specific human mutations that cause limb abnormalities ha ve been identified. Hand surgeons should be aware of the basic molecular pa thways controlling limb development because they are in a unique position t o be able to identify patients with such deformities. In turn, derailed cli nical descriptions of congenital anomalies affecting the upper extremity wi ll advance the understanding of the cellular events controlled by the molec ular pathways of limb development. This review describes the general molecu lar basis of limb development and correlates it with disease processes affe cting the upper extremity. (J Hand Surg 2001;26A:8-22. Copyright (C) 2001 b y the American Society for Surgery of the Hand.).