GENETIC-STUDY OF IDIOPATHIC TORSION DYSTO NIA IN RUSSIA

Inheritance of idiopathic torsion dystonia (ITD) was studied in 41 Rus sian families including 41 probands with generalized, focal; and segme ntal dystonia and 140 recurred cases. Affected relatives appeared in t wo or more generations in 31 families analyzed. It was shown that in 7 6% of segregated cases, ITD was inherited as an autosomal dominant tra it with a penetrance of 40% and varying expression. An autosomal reces sive type was observed in 24% of the cases. Approximately 10% of the c ases of disease could be caused by a new mutation and 14.6% by a nonge netic phenotype similar to genetic forms in its clinical symptoms. ITD with the X-linked recessive type of inheritance did not occur in the families studied The recurrence risk was 20% in autosomal dominant for ms. The risk correlated with age the relative's: clinical symptoms dev eloped in 98.4% of patients by the age of 30.