Genetic epidemiology of myotonic dystrophy in Istria, Croatia.

Abstract

We evaluated epidemiology of myotonic dystrophy in Istria, Croatia including direct mutation analysis as an additional, specific diagnostic criterion. Patients were ascertained in the period 1980-1994 from multiple sources under established clinical criteria with a special reference to congenital and minimal forms of the disease. Additionally, patients and their relatives were evaluated by direct mutation analysis. The prevalence, corrected for underascertainment, was estimated on July 1, 1989. A total of 33 DM patients from nine families were ascertained. In all families the diagnosis was confirmed by mutation analysis of the DM gene. After correction for underascertainment the prevalence of 18.1/100,000 was calculated. One of the highest prevalence estimates of DM in the populations without evidence of founder effect or genetic isolation was found. Our results imply the importance of ascertainment of patients with all forms of DM and utilization of specific diagnostic tests for estimation of genetic epidemiology in DM.