[Myotonic dystrophy. Genetic, neonatologic and neuropsychological aspects]

Dystrophia myotonica (DM) is an autosomally dominant hereditary multi-organ disease which is characterized primarily by myotonia and muscular atrophy and thereafter by cataract and disturbances in cardiac conduction. The prevalence is stated to be 2.5-5.5 per 100,000. The disease may be manifest at birth or may become manifest later, right up to the age of 60-70 years, on an average about the age of 20 years. The earlier the commencement of the disease, the more severe the course and the condition becomes crippling. The survival is reduced on an average by 25 years. The diagnosis is based on the clinical findings, information about familial occurrence of DM, electromyography and split lamp examination. The penetration of the DM gene is practically 100% by the age of 14 years but the expression varies greatly. By examination of chorion villi in informative families it will be possible to predict with 96-98% probability whether an embryo will develop DM or not. Genetic research in recent years has rendered prenatal diagnosis possible and diagnosis of the DM gene prior to conception in clinically healthy family members. No specific treatment is available.