genetic analysis of myotonic dystrophy patients

myotonic dystrophy (dm), one of the most common forms of muscular dystrophy, is an inherited disorder of the muscles and other body systems. dm is a progressive genetic disorder with a triplet repeat autosomal mutation that affects an estimated 1 in 8000 people. myotonic dystrophy type 1, also known as steinerts disease, and type 2 caused by mutation in dmpk and cnbp genes, respectively. in each case, an unstable region in the gene forms by abnormal repeating of a short segment of dna. dm1 is caused by an expanded and unstable (ctg)n trinucleotide repeat, located in the 3 untranslated region of the dystrophia myotonica-protein kinase (dmpk) gene on chromosome 19. the mutated gene produces an altered version of messenger rna, which is a molecular blueprint of the gene that is normally used for protein production. the abnormal messenger rna forms clumps inside the cell that interfere with the production of many proteins. the signs and symptoms of myotonic dystrophy are the result of the prevented cells in muscles and other tissues from functioning normally. myotonic dystrophy type 2 (dm2), also known as proximal myotonic myopathy (promm), is a milder form of myotonic dystrophy where transient muscle pain is the most common complaint. additional forms (dm3, dm4) have been suggested, as a small number of individuals have been seen who have the characteristic symptoms of myotonic dystrophy, but who do not have the genetic mutations which cause these disroders. considerable debate exists as to whether these individuals truly represent a new form of myotonic dystrophy or whether they simply present unique diagnostic challenges.we have tested the ctg trinucleotide repeat of the dmpk gene in our patients sample by pcr and page electrophoresis methods.