Valine codon 386 (GTG) and threonine codon 387 (ACA) in exon 12 were changed to glycine (GGC) (p.V386G, p.T387G or p.V386_T387delinsGG) and a loxP site flanked neomycin resistance gene cassette was inserted into the 3' UTR in exon 13. The neo cassette was removed through subsequent Cre-mediated recombination. (J:199658)