Myotonic dystrophy--early detection and genetic counselling.

Is is generally believed that because of the relatively high age of onset, early detection and genetic counselling in cases of myotonic dystrophy is difficult, if not impossible. Accordingly, clinical experience shows that the disease in many families was detected only after birth of the offspring, and was thus passed on over several generations. The aim of this study is to determine the age at which the expected rate of affection of 50% in the different sibs is found.