symphalangism proximal syndrome

Pathology

• conductive hearing loss due to fusion of the stapes to the petrous part of the temporal bone

Genetics

• associated with defects in NOG gene
• associated with defects in GDF5 gene

Clinical manifestations

• hereditary absence of proximal interphalangeal joints (Cushing symphalangism) - severity diminishes towards radial side
• distal intrphalangeal joints are less frequently involved
• metacarpophalangeal joints are rarely affected
• carpal bone malformation & fusion are common
• in the lower extremities, tarsal bone coalition is common
• conductive hearing loss

More general terms

• genetic syndrome (multisystem disorder)
• developmental disorder

Database

• OMIM: https://mirror.omim.org/entry/185800