An A to G splice mutation was introduced betweeen exon 13 and 14 along with humanization of the coding sequence of exon 15 through the following sequence changes: g.14230 C to T, g.14232 A to T, g.14234 C to G, g.14260 A to G, and g.14266 ATTA insertion. Flp-mediated recombination removed the FRT-flanked neomycin resistance cassette. (J:249965)