Lafora disease is not linked to the Unverricht-Lundborg locus

Lafora disease and Unverricht-Lundborg disease are two forms of progressive myoclonus epilepsies (PME). Recently the gene for Unverricht-Lundborg disease (EPM1) was mapped to chromosome 21q22.3. Using three highly polymorphic DNA markers (D21S212, PFKL, and D21S171) which flank the EPM1 locus, we performed linkage analysis to investigate whether or not the EPM1 gene is also implicated in Lafora disease. Linkage was excluded in three North-African pedigrees each comprising at least two affected individuals. This result suggests that differential diagnosis of Lafora disease and Unverricht-Lundborg disease may be facilitated by molecular genetic analysis.