A guanine to adenine transition at base 518 in exon 3 causes a change in codon 167 with the replacement of arginine by glutamine (R518Q) in the resulting protein. A floxed neomycin cassette was inserted in intron 2 as well. Transient transfection with a cre expressing vector resulted in excision of the neomycin selection cassette. (J:157369)