Analysis of CAG repeat expansion in Huntington's disease gene (IT 15) in aHungarian population

Huntington's disease (HD) is a neurodegenerative disorder with autosomal do minant inheritance. The genetic defect is a CAG trinucleotide repeat expans ion at the 5' end of the IT 15 gene on chromosome 4, This gene has not been analyzed in the Hungarian population yet. To obtain data DNA from 26 HD pa tients, 18 members of their families and 70 normal controls was amplified i n the involved region by polymerase chain reaction. The CAG repeat numbers varied from 37 to 70 (median: 43) in HD patients and asymptomatic carriers, while individuals of the normal control group had 10-36 CAG repeat numbers (median: 18). The length of CAG repeat expansion in Hungarian HD patients was similar to that reported from other countries. The group of normal cont rols had the same CAG repeat expansion as populations reported from Western European countries. It is a useful piece of data for population genetics t o prove that the population of Hungary is a melange of different nations th at influenced the history of the country in the last 11 centuries. As oppos ed to this, the only closely related nation, the Finnish, was genetically m ore isolated during this time, so the frequency of HD land also the number of CAG repeats in normal individuals) proved to be exceptionally low.