Two point mutations were introduced to exon 1 of the gene. The first was a silent C>G, to eliminate a Hinf1 restriction site to aid in genotyping, and the second was the pathogenic A>G, to introduce the p.Y141C substitution in the encoded protein. An frt site flanked neomycin selection cassette was removed via Flp-mediated recombination. (J:215646)