CTG repeat polymorphism in DMPK gene in healthy Yugoslav population.

Objectives - Myotonic dystrophy type 1 (DM1) is caused by large expansions of cytosine-thymine-guanine (CTG)-repeats in myotonic dystrophy protein kinase (DMPK)-gene. This gene is highly polymorphic in healthy individuals. It has been proposed that expanded alleles originated from the group of large sized normal alleles. If this is correct, one should expect a positive correlation between the frequency of large sized normal alleles and a prevalence of this disorder in a population. In this paper we determined the distribution of alleles of DMPK gene in healthy Yugoslav population. Material and methods - A sample of 235 healthy individuals of Yugoslav origin have been genotyped for the alleles of DMPK locus. Results - We found 22 different alleles, ranging in size from 5 to 29 repeats. Among 470 chromosomes studied, 41 chromosomes had more than IX repeats (8.72%). Conclusions - Relatively high frequency of large sized normal alleles found in our population, suggest that prevalence of DM1 in Yugoslavia should not be different from the prevalence in other European populations.