Constriction band syndrom syndactyly is a sporadic condition, that may be present in association with other congenital anomalies such as musculoskeletal (including total amputation of the limb), craniofacial (like cleft lip and cleft palate) and thoraco-abdominal disorders (such as gastroschisis and extrathoracic heart), neural tube defects, scoliosis and hemangiomas (1, 2, 3, 4, 5, 6). Some of these manifestations are uncommonly noted at birth because they result in spontaneous abortion.
There are two main theories about constriction band syndrome etiology, the first of which is the intrinsic theory proposed by George Streeter, the director of embryology at Carnegie Institute, in 1930 which is called, "Streeter’s Dysplasia". Streeter suggested that an intrinsic defect in the subcutaneous germplasm resulted in focal mesenchymal hypoplasia, tissue loss, and scarring (7, 8).

Syndactyly is one of the two most common congenital hand abnormalities, the other being polydactyly (1, 2, 3). It occurs in about 1: 2,500 live births, more commonly in males, and is most often seen in the third web space (2, 4). The condition has a strong familial tendency and is bilateral in half of the cases (4, 2, 5). Inheritance is thought to be autosomal dominant with variable penetrance and expressivity, which may explain the male predominance (6).
Unlike secondary syndactyly, which occurs due to abnormal fusion of initially individualized fingers, primary syndactyly mainly occurs due to the failure of differentiation between adjacent digits, caused by the absence of apoptosis in the interdigital mesenchyme during the seventh and eighth weeks of gestation (7,8). Syndactyly may occur as an isolated event or it may be linked to other anomalies in the body, being known as syndromic syndactyly (7).