Myotonic dystrophy (DM)

 

 

 

MD is inherited as an autosomal dominant disorder which is caused by expansion of unstable trinucleotide repeat (CTG)n in the gene for myotonin protein kinase, located on chromosome 19q13.3. The trinucleotide repeat, which is present 5-40 times in normal individuals, expands to 42-100 in mildly affected patients, to 100-1,000 in classical MD and has been found to amplify up to 2,000 times in congenitally affected patients (there is some overlap between the different groups). The test identifies the number of repeats in an individual’s MD gene, categorising the individual as either carrying two normal alleles, or one normal allele with either a borderline normal allele, a premutation or a full mutation.  We uesd expand PCR system to identify the expansion of CTG repeat.

 

Indications for testing

• Confirmation of diagnosis, in the case of any association of the typical symptoms for MD, which vary from cataracts and below normal intelligence to severe hypotonia and respiratory difficulties.

2) Prenatal diagnosis is indicated in cases where either the mother or father has been diagnosed with MD, based on the results of the DNA test.

3) At-risk relatives of individuals either diagnosed with or suspected of having MD, regardless of clinical expression.

Contact us: Tel:(+98 21)88003811-12