A transition of C to T results in the amino acid substitution of serine with leucine at position 220 (p.S220L), replicating the S218L mutation found in some familial hemiplegic migraine type 1 (FHM1) patients. A loxP site flanked neomycin resistance gene cassette inserted upstream of exon 5 was removed through germ line cre-mediated recombination. (J:144701, J:211767)