Type of disease: Rare conditions
Cushing's symphalangism, which is also called proximal symphalangism, is a rare genetic condition characterized by the fusion of the proximal joints in the hands and feet. These individuals usually have straight fingers and are unable to make a fist. Other joints may also be affected, leading to stiff joints in the elbows, ankles and wrists. Hearing loss due to the fusion of the auditory ossicles (bones in the middle ear) is also a characteristic feature. This condition is inherited in an autosomal dominant pattern and is caused by a mutation in the NOG gene or GDF5 gene. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.