A novel stroke locus identified in a northern Sweden pedigree: Linkage to chromosome 9q31-33

The population of northern Sweden is characterized by reduced genetic diversity and a high incidence of stroke. We sought to reduce genetic variation further, using genealogic analysis in a set of nuclear families affected by stroke, and we subsequently performed a genome-wide scan to identify novel stroke susceptibility loci. Through genealogy, 7 nuclear families with a common ancestor, connected over 8 generations, were identified. A genome-wide scan using 449 microsatellite markers was performed with subsequent haplotype analyses. A maximum allele-sharing lod score of 4.81 on chromosome 9q31-q33 was detected. Haplotype analysis identified a common 2.2-megabase interval in the chromosomal region in 4 of the nuclear families, where an overrepresentation of intracerebral hemorrhage was observed. We have identified a novel susceptibility locus for stroke. Haplotype analysis suggests that a shared genetic factor is of particular importance for intracerebral hemorrhage.