Mesomelia-Synostoses syndrome (MSS) is a syndromal osteochondrodysplasia due to a contiguous gene deletion syndrome, characterized by progressive bowing of forearms and forelegs leading to mesomelia, progressive intracarpal or intratarsal bone fusion and fusion of metacarpal bones with proximal phalanges, ptosis, hypertelorism, abnormal soft palate, congenital heart defect, and ureteral anomalies.

Webbing or fusion of the fingers or toes, involving soft parts only or including bone structure. Bony fusions are referred to as \"bony\" syndactyly if the fusion occurs in a radio-ulnar axis. Fusions of bones of the fingers or toes in a proximo-distal axis are referred to as \"symphalangism\".