Clinical features
Single changes (mutations) in the PIEZO2 gene are a recently discovered cause of several muscle conditions (congenital myopathies) that manifest with inborn joint contractures of hand and feet and reduced muscle mass (distal arthrogryposis multiplex congenital). Typically, there are associated features such as cleft palate, droopy eyelids or other eye findings, proportionate short stature, scoliosis and normal intelligence. Two of these conditions (Gordon syndrome, DA3, and oculomelic amyoplasia, DA5) are primarily non-progressive myopathies, with a long-term prognosis that is usually good. DA3 and DA5 are inherited with a 50% probability of an affected person passing the gene change on to any child (autosomal dominant inheritance).
A third condition, called DAIPT, is caused by the combination of two PIEZO2 gene mutations, that are usually passed on, one from each healthy parent, to an affected child (autosomal recessive inheritance). This means a probability of 25% that any sibling could also be affected by DAIPT. DAIPT usually presents at birth with multiple joint contractures, always involving feet and often hands. Breathing difficulties in newborns may require breathing support. The low muscle tone and contractures cause delayed motor development whilst intellectual development is usually not affected. Mildly reduced sensitivity to touch may be difficult to detect clinically. Scoliosis with subsequent impairment of lung function is one of the major long-term complications of this disease.