A Novel De Novo MTM1 Insertion Frameshift Variant Causes X-Linked Myotubular Myopathy in a Chinese Female.
Lijun Chen, Yingxiao Bao, Gonglu Liu
✦ AI-curated · Sources linked
Case in brief
A 24-year-old woman presented with infantile hypotonia and progressive, asymmetric proximal weakness, including facial and ocular involvement. Clinical evaluations revealed significant respiratory impairment, a myopathic pattern on electromyography, and extensive fatty replacement on muscle MRI. Muscle biopsy indicated centronuclear myopathy. Genetic testing identified a novel de novo MTM1 insertion variant causing a frameshift, contributing to her X-linked myotubular myopathy.
What made this case unusual
This case is notable for the identification of a novel de novo MTM1 insertion variant in a female patient, which is atypical as X-linked myotubular myopathy predominantly affects males.
Diagnostic / clinical pearl
Clinicians should consider genetic testing for MTM1 variants in symptomatic female patients presenting with features of centronuclear myopathy.
Why it matters
This case emphasizes the importance of recognizing that X-linked myotubular myopathy can manifest in females, expanding the understanding of its genetic spectrum.