Multiple synostoses syndrome (MSS) is a rare developmental bone disorder characterized by proximal symphalangism of the fingers and/or toes often associated with fusion of carpal and tarsal, humeroradial, and cervical spine joints. The disease is MONDO_0017923 (multiple synostoses syndrome). Also known as: WL syndrome, deafness-Hermann type symphalangism syndrome, facio-audio-symphalangism, symphalangism-brachydactyly syndrome.