nemaline myopathy type 5
nemaline myopathy type 5A form of nemaline myopathy (OMIM:605355), a family of muscular disorders characterised by muscle weakness of varying severity and onset, and abnormal thread- or rod-like structures in muscle fibres on histologic examination. NEM5 is a severe and progressive form seen in Old Order Amish. Affected infants display tremors with hypotonia and mild contractures of the shoulders and hips; proximal contractures progressively weaken and a pectus carinatum develops before infants die of respiratory insufficiency, often by age 2.
Caused by defects of TNNT1, which encodes type-1 troponin T, the slow skeletal troponin T subunit.