Rapid detection of expansions by PCR and non-radioactive hybridization: application for prenatal diagnosis of myotonic dystrophy

The mutation specific for myotonic dystrophy (DM) is an unstable expanded C TG repeat located in the 3'-untranslated region of the myotonin protein kin ase gene. Expansion of the CTG repeat shows a positive correlation with the severity of the disease and increases in successive generations of DM pati ents. Children with the congenital form of DM show the most severe phenotyp e and have large expansions, usually >1000 repeats. For pregnant women with DM, prenatal diagnosis of DM may be offered, To reduce the time between ch orionic villus sampling or amniocentesis and final results of DNA analysis in these cases, a fast and efficient method has been developed. This method combines direct PCR analyses Tar normal alleles with a nested PCR system f ollowed by non-radioactive hybridization with a single-stranded probe. Copy right (C) 2000 John Wiley & Sons, Ltd.