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Published on: July 29, 2016
Two Cases of X-Linked Myotubular Myopathy with Novel MTM1 Mutations
Eun Hye Lee1, Mi-Sun Yum, Seong Jong Park
1Department of Pediatrics, College of Medicine, Kyung Hee University, Seoul, Korea.
Background:
Myotubular myopathy (MTM) is a congenital myopathy characterized by centrally placed nuclei in muscle fibers. Mutations in the myotubularin 1 gene (MTM1) have been identified in the most of the patients with the X-linked recessive form.
Case Report:
This report describes two male infants with X-linked MTM (XLMTM). Both patients presented with generalized hypotonia and respiratory difficulties since birth. We did not perform a muscle biopsy in either patient, but their conditions were diagnosed by genetic testing of MTM1. One splicing mutation, c.63+1G>C, and a frame-shift mutation, c.473delA (p. Lys158SerfxX28), were identified. Neither mutation has been reported previously.
Conclusions:
Genetic testing for MTM1 is helpful for the differential diagnosis of floppy male infants. We suggest that advanced molecular genetic testing may permit a correct diagnosis while avoiding invasive procedures.
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