TPM3-related myopathy is a disorder of the musculoskeletal system that covers a wide spectrum of phenotypes and is caused by pathogenic variants in the skeletal muscle γ-Tropomyosin gene. These variants lead to a variety of overlapping adult onset and congenital myopathies characterized by muscle weakness, hypotonia, motor delay, myopathic facies, scoliosis, and sometimes respiratory involvement. Histologic findings on skeletal muscle biopsy are variable with nemaline and intranuclear bodies, cap-like lesions, fiber-type disproportion, and dystrophic features even in patients with the same mutation. The disease is Monarch Disease Ontology entry MONDO_0100108 (TPM3-related myopathy). Also known as: TPM3 myopathy, congenital myopathy related to TPM3.