PREVALENCE OF MYOTONIC-DYSTROPHY IN GUIPUZCOA (BASQUE COUNTRY, SPAIN)

Prevalence figures for inherited neuromuscular disorders are important both for health care planning purposes and for evaluating the need fo r DNA diagnostic services for eugenic approaches. We screened for the prevalence of myotonic dystrophy (MyD) through extensive inquiry of ne urologic and primary health services of Guipuzcoa (Basque Country, nor thern Spain) between 1989 and 1991. Typical adult-onset and neonatal c ases and relatives at risk, suffering from a partial syndrome, were in cluded. In the latter, molecular typing was performed with DNA probes close to the MyD gene to demonstrate the MyD gene carrier status. The high prevalence detected (26.5 cases per 100,000 population) could be explained by methodological factors, but intrinsic factors, such as a possible founder genetic effect or the quick growth of the Guipuzcoa p opulation since the last century may contribute to one of the highest MyD prevalences in the world. In the future, the methodological basis for epidemiologic surveys of MyD must combine molecular technology wit h more-extensive family inquiries.