Disease relevance of Myopathies, Structural, Congenital

• The human neuromuscular diseases X-linked myotubular myopathy and Charcot-Marie-Tooth disease type 4B are caused by mutations in myotubularin family proteins [1].
• Comparison of this deletion with that carried by a male patient with a severe Hunter syndrome phenotype but no myotubular myopathy, in light of recent linkage data on recombinant MTM1 families, led to a considerable refinement of the position of the MTM1 locus, to a region of approximately 600 kb, between DXS304 and DXS497 [2].
• We report on the first case of X-linked recessive myotubular myopathy (MTM1) coinciding with Duchenne muscular dystrophy (DMD) [3].
• X-linked recessive myotubular myopathy (XLMTM) is a muscle disorder usually affecting newborn males [4].
• X-linked myotubular myopathy is characterised by neonatal hypotonia, muscle weakness and respiratory distress in affected males, leading often to early death, although prolonged survival is observed in milder forms, or as a result of prolongation of ventilation support [5].

High impact information on Myopathies, Structural, Congenital

• Mutations in dynamin 2 cause dominant centronuclear myopathy [6].
• A gene mutated in X-linked myotubular myopathy defines a new putative tyrosine phosphatase family conserved in yeast [7].
• Centronuclear myopathy in mice lacking a novel muscle-specific protein kinase transcriptionally regulated by MEF2 [8].
• Crystal structure of a phosphoinositide phosphatase, MTMR2: insights into myotubular myopathy and Charcot-Marie-Tooth syndrome [9].
• Mutations in members of the myotubularin family cause the human neuromuscular disorders myotubular myopathy and type 4B Charcot-Marie-Tooth syndrome [9].

Chemical compound and disease context of Myopathies, Structural, Congenital

• Abnormal skeletal muscle biopsies showed "ragged-red" fibers or congenital fiber type disproportion; serum alanine levels were elevated; in-vivo and in-vitro tests of pyruvate metabolism gave abnormal results; C4 complement was decreased; and the patients' fibroblasts bound immunoglobulin when incubated with autologous serum [10].
• Inaugural article: myotubularin, a protein tyrosine phosphatase mutated in myotubular myopathy, dephosphorylates the lipid second messenger, phosphatidylinositol 3-phosphate [11].
• Centronuclear myopathy and type-1 hypotrophy without central nuclei. Distinct nosologic entities [12]?
• Steroid-responsive tubular aggregate myopathy [13].
• A 2.5-year-old boy with known myotubular myopathy (Spiro-Shy-Gonatas syndrome) and gonadorelin intake 9 months ante-mortem was found dead in his bed at home [14].

Biological context of Myopathies, Structural, Congenital

• Although the function of PTPLA in metazoa remains unknown, the characterization of a hypomorphic mutation in Labradors with centronuclear myopathy provides new clues about the molecular complexity of skeletal myofiber homeostasis [15].
• A three generation family with X linked myotubular myopathy (MTM1) was studied with several polymorphic markers from the distal long arm of the X chromosome [16].
• X linked myotubular myopathy (MTM1) maps between DXS304 and DXS305, closely linked to the DXS455 VNTR and a new, highly informative microsatellite marker (DXS1684) [17].
• X-linked myotubular myopathy: refinement of the gene to a 280-kb region with new and highly informative microsatellite markers [18].
• X-linked recessive myotubular myopathy: II. Muscle morphology and human myogenesis [19].

Anatomical context of Myopathies, Structural, Congenital

• Within this group of disorders, congenital X-linked recessive myotubular myopathy (XLMTM), characterized by marked cell hypotrophy and structural resemblance to fetal myotubes, represents a distinct entity [19].
• Detection of a new polymorphism in the plasma-membrane Ca2+ ATPase isoform-3 gene and its exclusion as a candidate for X-linked myotubular myopathy (MTM1) [20].
• X-linked recessive myotubular myopathy is associated with overexpression of vimentin and desmin, fetal intermediate filaments that attach to nuclear, mitochondrial, and inner sarcolemmal membranes and Z-bands of sarcomeres to preserve the morphologic organization of the myotube [21].
• Ribosomes isolated from fibroblasts, muscle tissues, and blood cells of a patient with congenital non-progressive myopathy were used for in vitro measurement of protein synthesis in a heterologous poly(U)-directed polyphenylalanine synthesis system [22].

Gene context of Myopathies, Structural, Congenital

• Myotubularin (hMTM1), the founder member, is mutated in myotubular myopathy, and a close homolog (hMTMR2) was recently found mutated in a recessive form of Charcot-Marie-Tooth neuropathy [23].
• Myotubularin and MTMR2, phosphatidylinositol 3-phosphatases mutated in myotubular myopathy and type 4B Charcot-Marie-Tooth disease [24].
• SINE exonic insertion in the PTPLA gene leads to multiple splicing defects and segregates with the autosomal recessive centronuclear myopathy in dogs [15].
• MTM1 is mutated in X-linked myotubular myopathy, and MTMR2 and MTMR13 are mutated in Charcot-Marie-Tooth syndrome [25].
• Inactivating mutations in the genes encoding PTEN and Myotubularin are key steps in the progression of some cancers and in the onset of X-linked myotubular myopathy, respectively [26].

Analytical, diagnostic and therapeutic context of Myopathies, Structural, Congenital

• Confirmation of prenatal diagnosis results of X-linked recessive myotubular myopathy by mutational screening, and description of three new mutations in the MTM1 gene [27].
• We investigated plectin immunocytochemistry in lobulated fibers, fibers with tubular aggregates, target fibers, central core disease and centronuclear myopathy [28].

References