Pterygium, Antecubital

Description

Antecubital pterygium syndrome is an autosomal dominant disorder characterized by a fleshy web extending across the anterior aspect of the cubital fossa, absence of the long head of the triceps, limitation of full elbow extension, and missing skin creases over the terminal interphalangeal joints of the fingers (summary by Wallis et al., 1988).

Clinical Features

Shun-Shin (1954) described 8 affected individuals in 3 generations of a family living on the Island of Rodriques (near the island of Mauritius). There was 1 instance of a 'skipped generation.' The web extended across the cubital fossa from the distal third of the upper arm to the proximal third of the forearm. Elbow extension was limited to 90 degrees, although flexion was unimpeded. Radiologically, posterior subluxation of the radial head (179200) and maldevelopment of the radioulnar joint were demonstrated. The same disorder was reported by Zahrt (1903) in a father and son. An isolated example was noted by Schramm (1939-40).

Wallis et al. (1988) provided follow-up on the family reported by Shun-Shin (1954). Eleven members in 5 generations were affected.

In commenting on the family reported by Wallis et al. (1988), Hall (1990) noted that the great-great-grandfather, who was designated as the 'founder of the dynasty,' was the only one of 11 affected persons on whom information was available to have unilateral involvement. Hall (1990) suggested that he had both somatic and germline mosaicism and was indeed the individual in whom the new mutation occurred during his embryologic development. Hall (1988) had emphasized the importance of somatic mutation, and stated that this case raised the question of whether most mutations may in fact occur during mitosis rather than in meiosis.

Inheritance

The presence of affected persons of both sexes in 5 generations of the family reported by Wallis et al. (1988) indicated that the antecubital pterygium syndrome is inherited as an autosomal dominant trait.