Positive association between benign familial infantile convulsions and LGI4

Purpose:LGI4 is located in 19q13.11, where the locus of benign familial infantile convulsions (BFIC) has been mapped. LGI4 belongs to a family of proteins with the epilepsy-associated repeat (EAR) domain and is associated with various epilepsies. We investigated whether LGI4 is a candidate gene for BFIC. Methods: Fifteen patients with BFIC were examined for mutations and/or polymorphisms of LGI4 by using a direct sequencing method. Results: Several frequent polymorphisms were identified. The genotype frequency distribution of c.1722G/A polymorphism was significantly different between patients with BFIC and control subjects (p < 0.05). Logistic regression analysis showed that the G allele of c.1722G/A polymorphism had significant recessive effects on the increased relative risk for BFIC (p < 0.05). There was no association between c.1722G/A polymorphism and benign familial neonatal convulsion, an epilepsy phenotype similar to BFIC but genetically distinguished from BFIC. Discussion: The positive genotypic association between BFIC and c.1722G/A polymorphism suggests that LGI4 might contribute to the susceptibility to BFIC.