Gene expression analyses in X-linked myotubular myopathy.

Abstract

X-linked myotubular myopathy (XLMTM) is a severe congenital disorder characterized by marked muscle weakness and hypotonia. Myotubularin, the protein product of the causative gene, MTM1, is thought to be a phosphatase for phosphatidylinositol-3-phosphate and may be involved in membrane trafficking. Analysis of MTM1 knocked-out mice indicates that the characteristic small fibers in XLMTM muscles are due to atrophy rather than hypoplasia. To characterize gene expression profiling of skeletal muscles with XLMTM. The authors analyzed the expression of more than 4,200 genes in skeletal muscles from eight patients with XLMTM using their custom cDNA microarray. In XLMTM, gene expression analysis revealed pathognomonic upregulation of transcripts for cytoskeletal and extracellular matrix proteins within or around atrophic myofibers. Remodeling of cytoskeletal and extracellular architecture appears to contribute to atrophy and intracellular organelle disorganization in XLMTM myofibers.