A Case of Myotubular Myopathy

ABSTRACT

The term myotubular myopathy (MTM) implies a maturational arrest of fetal muscle during the myotubular stage of development at 8-15 weeks of gestation. Characteristic muscle histopathology consists of small hypotrophic muscle fibers with centrally placed nuclei and a surrounding clear area devoid of myofibrils. X-linked recessive inheritance is the most common trait. Autosomal recessive and autosomal dominant forms are less frequently reported. The clinical diagnostic criterion for X-linked MTM has relied on a positive family history and the demonstration of the presence of characteristic biopsy findings from affected male subjects. Additional features may include perinatal onset, severe hypotonia, respiratory failure, dysphagia, thin ribs, contractures of the hips or knees, puffy eyelids and ophthalmoplegia. The prognosis is often fatal, and most patients die within the first year of life from respiratory failure. The authors report a case of presumed X-linked MTM with severe hypotonia, muscle weakness and respiratory failure at birth.