Autosomal dominant
Caused by changes in one copy of NOG, which encodes noggin, a protein that limits BMP signalling to allow joints to form. Changes can be inherited, and features vary within families.
Signs and symptoms
Fusion of the joints of the fingers, usually the joint closest to the knuckle, causing stiff fingers that cannot bend fully, often with fused wrist or ankle bones. Conductive hearing loss from fusion of the stapes bone in the middle ear is common. Less often there are short fingers, broad thumbs and toes, or limited elbow movement.
What a diagnosis changes
Hearing assessment, with hearing aids or stapes surgery for conductive hearing loss, and hand therapy or orthopaedic advice. Each child of an affected person may inherit the change, so genetic counselling and testing of relatives are offered.
Genes analysed
Also known as
NOG-SSD
Includes 5 related subtypes ↓Hide subtypes ↑
- brachydactyly type B2
- multiple synostoses syndrome 1
- proximal symphalangism 1A
- stapes ankylosis with broad thumbs and toes
- tarsal-carpal coalition syndrome
