[A novel mutation of KCNQ2 gene in a Chinese family with benign familial neonatal convulsions].

OBJECTIVE To diagnose a Chinese benign familial neonatal convulsions (BFNC) family at the level of gene and investigate its molecular pathogenesis. METHODS All family members were studied by clinical examinations and linkage analysis. Mutation analysis of KCNQ2 gene was made by means of polymerase chain reaction (PCR)-direct sequencing and PCR-single strand conformation polymorphism (SSCP) in the proband, 16 family members and 72 unrelated normal individuals. RESULTS Linkage analysis hinted the linkage of BFNC to KCNQ2, while the linkage to KCNQ3 was excluded. Mutation 1931delG of KCNQ2 gene was found in the proband by DNA-direct sequencing. The same SSCP variant as the proband's was showed in the rest affected members of this family but not in the unaffected members of this family and all of the 72 unrelated normal individuals. CONCLUSION 1931delG of KCNQ2 gene can cause BFNC in China and is novel mutation. The combination of linkage analysis and gene analysis is useful for gene diagnosis.