Nijmegen breakage syndrome is a rare genetic disease presenting at birth with microcephaly, dysmorphic facial features, becoming more noticeable with age, growth delay, and later-onset complications such as malignancies and infections.

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\".