Benign familial infantile convulsions: Mapping of a novel locus on chromosome 2q24 and evidence for genetic heterogeneity

In 1997, a locus for benign familial infantile convulsions (BFIC) was mappe d to chromosome 19q. Further data suggested that this locus is not involved in all families with BFIC. In the present report, we studied eight Italian families and mapped a novel BFIC locus within a 0.7-cM interval of chromos ome 2q24, between markers D2S399 and D2S2330. A maximum multipoint HLOD sco re of 6.29 was obtained under the hypothesis of genetic heterogeneity. Furt hermore, the clustering of chromosome 2q24-linked families in southern Ital y may indicate a recent founder effect. In our series, 40% of the families are linked to neither chromosome 19q or 2q loci, suggesting that at least t hree loci are involved in BFIC. This finding is consistent with other autos omal dominant idiopathic epilepsies in which different genes were found to be implicated.