MedGen

Tubular aggregates in muscle, first described by Engel (1964), are structures of variable appearance consisting of an outer tubule containing either one or more microtubule-like structures or amorphous material. They are a nonspecific pathologic finding that may occur in a variety of circumstances, including alcohol- and drug-induced myopathies, exercise-induced cramps or muscle weakness, and inherited myopathies. Tubular aggregates are derived from the sarcoplasmic reticulum (Salviati et al., 1985) and are believed to represent an adaptive mechanism aimed at regulating an increased intracellular level of calcium in order to prevent the muscle fibers from hypercontraction and necrosis (Martin et al., 1997; Muller et al., 2001). Genetic Heterogeneity of Tubular Aggregate Myopathy See also TAM2 (615883), caused by mutation in the ORAI1 gene (610277) on chromosome 12q24. [from OMIM]

A rare congenital myopathy characterized ultrastructurally by the presence of tubular aggregates in the subsarcolemmal region of the muscle fiber. It most commonly presents with slowly progressive proximal muscle weakness predominantly of the lower limbs, periodic paralysis, post-exertion muscle cramps, and muscular pain. Ocular anomalies like ophthalmoplegia or pupillary abnormalities may be associated. The intensity of the symptoms is variable, cases with normal muscle strength but myalgia or fatigue, as well as clinically asymptomatic cases have been described. [from ORDO]