Myotonic dystrophy is the most common form of muscular dystrophy that begins in adulthood and has a frequency of 1/8.000 individuals. Myotonic dystrophy is characterized by progressive muscle wasting and weakness. Patients often have prolonged muscle contractions (myotonia) and are not able to relax certain muscles after use. Other common symptoms are muscle weakness, development of cataract, cardiac defects and hypogonadism.
There are two major types of myotonic dystrophy: type 1 (DM1) and type 2 (DM2) and both are inherited in an autosomal dominant manner. Their signs and symptoms overlap, although type 2 tends to be milder than type 1.
Myotonic dystrophy type 2 is caused by the tetranucleotide CCTG expansion in intron 1 of ZNF9 gene. More than 75 repeats are pathogenic and are associated with disease development. The higher number of repeats is generally associated with increased disease severity.
The number of CCTG repeats in ZNF9 gene is analysed using PCR and subsequent fragment analysis in a Genetic Analyser.
Sample type: Peripheral blood in EDTA
Time to result: 2 weeks
Prenatal diagnosis for myotonic dystrophy type 2 is possible, please contact us for more information.