DIRECT GENETIC DIAGNOSIS OF HUNTINGTONS-D ISEASE

Huntington's disease is a late manifesting autosomal dominant neurodeg enerative disorder. It is characterized by motor disturbance, loss of cognitive functions and psychiatric manifestations. Recently, the dise ase causing mutation, an unstable DNA sequence in the coding region of the Huntington gene on chromosome 4p, has been identified. A trinucle otide (CAG) repeat is expanded over the normal range and can easily be detected by standard laboratory methods. Accurate genetic testing can now be offered in clinically questionable cases and to subjects at ri sk for Huntington's disease. Furthermore, there seems to be a correlat ion between the size of the expanded CAG repeat and the age of onset i n affected individuals. We have investigated more than 130 individuals from different affected families and illustrate the advantages and th e clinical application of the new method.