title: Extreme phenotypic variability in a German family with X-linked myotubular myopathy associated with E404K mutation in MTM1.
abstract: X-linked myotubular myopathy (XLMTM) is a congenital muscle disorder caused by mutations in the MTM1 gene. Affected males usually present at birth with severe hypotonia and respiratory insufficiency, and most of them die within the first few years of life. We report here on a 68-year-old patient with a very mild form of the disease who was diagnosed after his grandson showed muscular weakness and respiratory problems at birth. The E404K mutation in the MTM1 gene was found in both patients. To our knowledge, this grandfather is one of the oldest and most mildly affected known patients with an MTM1 mutation to date. Thus, this family represents a remarkable phenotypic variation of XLMTM ranging from a congenital to a mild adult form.
authors.affiliation: Department of Human Genetics, Ruhr-University Bochum, Germany. sabine.hoffjan@rub.de
authors.forename: Sabine
authors.initials: S
authors.lastname: Hoffjan
authors.forename: Charlotte
authors.initials: C
authors.lastname: Thiels
authors.forename: Matthias
authors.initials: M
authors.lastname: Vorgerd
authors.forename: Eva
authors.initials: E
authors.lastname: Neuen-Jacob
authors.forename: Jörg T
authors.initials: JT
authors.lastname: Epplen
authors.forename: Wolfram
authors.initials: W
authors.lastname: Kress
mesh_terms: D000368:Aged; D002675:Child, Preschool; D005091:Exons / Q000235:genetics; D005260:Female; D040181:Genetic Diseases, X-Linked / Q000235:genetics* / Q000473:pathology; D005858:Germany; D006801:Humans; D007223:Infant; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology / Q000503:physiopathology; D009154:Mutation / Q000235:genetics*; D020914:Myopathies, Structural, Congenital / Q000235:genetics* / Q000473:pathology; D010375:Pedigree; D010641:Phenotype; D017027:Protein Tyrosine Phosphatases / Q000235:genetics*; D054558:Protein Tyrosine Phosphatases, Non-Receptor; D044465:White People / Q000235:genetics
chemical_list: D017027:Protein Tyrosine Phosphatases; D054558:Protein Tyrosine Phosphatases, Non-Receptor; C099588:myotubularin