IDENTIFICATION OF A RECOMBINATION EVENT NARROWING THE LAFORA-DISEASE GENE REGION

Patients affected with progressive myoclonus epilepsy of the Lafora ty pe present during late adolescence with a characteristic EEG pattern a nd Lafora bodies seen on skin biopsy. The critical region for the Lafo ra gene has been localised to chromosome 6q24 flanked by the dinucleot ide repeat markers D6S292 and D6S420. This study for linkage of marker s from the candidate gene region was performed in a previously unpubli shed family affected with Lafora disease. EEG and skin biopsy evaluati on for Lafora bodies were performed on five of eight family members fo llowed for seizure activity. Haplotype and linkage analysis of DNA fro m five family members were carried out using the nine dinucleotide rep eat markers reported in the common region of homozygosity by Serratosa et al in 1995. The present study of an additional family affected by Lafora disease has narrowed the 17 cM critical region for the Lafora d isease gene on chromosome 6q24 to a 4 cM region flanked by markers D6S 308 and D6S311.