CORRELATION OF CLINICAL PROFILE OF MYOTONIC-DYSTROPHY WITH CTG REPEATS IN THE MYOTONIN PROTEIN-KINASE GENE

The molecular genetic analyses (PCR and Southern hybridization) of Ind ian patients with myotonic dystrophy (DM) were carried out to determin e the degree of repeat expansion and an attempt was made to correlate the repeat number with disease severity. A scoring system based on the salient clinical features was devised to objectively assess the disea se severity. The repeat expansion was seen in 11 of 12 patients examin ed and showed an inverse correlation with the age of onset confirming the phenomenon of anticipation. This was further established in the tw o pedigrees studied, dearly demonstrating both clinical and genetic an ticipation. The clinical severity score,, however, did not correlate w ell with the repeat number. Nonetheless, such molecular genetic analys es may have immense value as a screening procedure to identify premuta tions as well as in prenatal diagnoses.