An adult nemaline myopathy patient with respiratory and heart failure harboring a novel NEB variant

Nemaline myopathy is a heterogeneous disorder of skeletal muscle, and histologically characterized by the presence of nemaline bodies in muscle fibers. Patients with typical congenital form of nemaline myopathy initially present with proximal but later also distal muscle weakness, mostly involving facial and respiratory muscle. Cardiac involvement has been rarely observed especially in nebulin-related nemaline myopathy and there have been only two reports about nebulin-related nemaline myopathy patients with cardiac involvement. We present here the case of a 65-year-old woman manifesting slowly progressive distal myopathy with respiratory and heart failure. She harbored two variants in the nebulin gene, c.20131C > T (p.Arg6711Trp) and c.674C > T (p.Pro225Leu), and one of them, c.674C > T, was a novel variant. In this report, we discuss the pathogenicity of the novel variant and its association with clinical phenotypes including cardiac involvement.