XLMTM, a life-threatening monogenic neuromuscular disorder

What is XLMTM?

X-linked myotubular myopathy (XLMTM) is the most common and severe form of centronuclear myopathy (CNM), a family of disorders characterized by skeletal muscle weakness, which can vary in severity and often presents at birth or early infancy with onset commonly in utero.1,2 The majority of patients with CNM have a mutation in the MTM1 gene, making XLMTM the most common subtype.

Like other CNMs, XLMTM is characterized by large, central nuclei of the muscle fibers, which can be observed in muscle biopsies.2-4

Biopsy of healthy muscle fiber (left) and muscle fiber from a patient with XLMTM (right). Nuclei are shown in purple and muscle fibers in pink; arrows indicate enlarged central nuclei characteristic of CNM, compared with peripheral nuclei in healthy muscle tissue.

* XLMTM histology image courtesy of Dr. Michael Lawlor, MD/PhD, Director, Congenital Muscle Disease Tissue Repository, Medical College of Wisconsin.


1. Vandersmissen I, et al. Neuromuscul Disord. 2018;28(9):766-777. 2. McEntagart M, et al. Neuromuscul Disord. 2002;12(10):939-946. 3. North KN, et al. Neuromuscul Disord. 2014;24(2):97-116. 4. Lawlor MW, et al. J Neuropathol Exp Neurol. 2016;75(2):102-110.


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