Clinical features

The clinical features of ulnar dysplasia are very variable and usually less conspicuous than radial dysplasia:

• ulna hypoplasia (most common) or absence
• ulnar deviation at the wrist
• radius curved
• radial head dislocation
• hypoplasia of upper limb
• absences of metacarpals or digits (90%)
• syndactyly in a minority
• thumb or first web anomaly, but the extent of this does not bear any relation to the forearm anomaly

There may be associated generalised musculoskeletal dysplasias.