What is the definition or description of: fused fingers?

Syndactyly: Is a common congenital condition where webbing or attachments between fingers or toes persists until birth. During the development of a child in utero programmed cellular intructions lead to the separation of fingers and toes into distinct members. If something either genetic or familial or syndromic ( assocaited with other issues) interferes then the fingers/toes do not separate " normally".