PREDICTION OF MYOTONIC-DYSTROPHY CLINICAL SEVERITY BASED ON THE NUMBER OF INTRAGENIC [CTG](N) TRINUCLEOTIDE REPEATS

We carried out a genotype-phenotype correlation study, based on clinic al findings in 465 patients with myotonic dystrophy (DM), in order to assess [CTG] repeat number as a predictive test of disease severity. O ur analysis showed that the DM subtypes defined by strict clinical cri teria fall into three different classes with a log-normal distribution . This distribution is useful in predicting the probability of specifi c DM phenotypes based on triplet [CTG] number. This study demonstrates that measurement of triplet expansions in patients' lymphocyte DNA is highly valuable and accurate for prognostic assessment. (C) 1996 Wile y-Liss, Inc.