الفهرس 
MYOTONIC DYSTROPHY
Classification and Clinical Features of DM1Only 14 pages are availabe for public view
 |  | from | 130 |  |  |
| | | from | 130 | | |
Abstract
Myotonic dystrophy type 1 (DM1) also called dystrophia myotonica is an autosomal dominant disorder that results from expansion of unstable trinucleotide repeats in the 3’untranslated region of the dystrophia myotonica protein kinase (DMPK) gene. It is the most common form of adult onset muscular dystrophy, affecting 1:8000 individuals. It is a slowly progressing, highly variable inherited multisystemic disorder that can manifest at any age from birth to old age. It is characterized by wasting of the muscles, posterior subcapsular cataract, cardiac conduction defects, endocrine abnormalities and myotonia. It is classified into three forms; mild, classic and congenital according to CTG repeats number and age of onset.
DMPK gene is located on the long arm of chromosome 19q13.3. The number of CTG repeats varies greatly among individuals, but the average number in a healthy person is from 5-34, patients with DM1 have over 35 and can have as many as 2000 repeats. In general, the more repeats in the affected range that someone has, the earlier the age of onset of symptoms and the more severe the symptoms.
The gold standard for diagnosing myotonic dystrophy type 1 is molecular diagnosis that detects the size of CTG repeats in DMPK gene. It is also of a great value in the prediction of the severity of the phenotype.
The aim of this work was to implement a molecular diagnostic method for confirmation of myotonic dystrophy type 1 in a sample of Egyptian patients. The study included 80 subjects: 20 cases from families with DM1, 40 primary cataract patients as a potential pool of DMPK mutation and 20 healthy controls.
All subjects were subjected to full clinical and genetic history taking, complete clinical examination, Pedigree analysis (for DM1 patients), electromyographic examination, and serum creatine kinase level assessment.
Molecular analysis of DMPK gene mutation was done by expand Long PCR method and polyacrylamide gel electrophoresis for all subjects included in this study