A G to A transition at position 905 (c.G905A) resulting in an arginine to histidine substitution at amino acid 302 (p.R302H) was introduced in exon 4. In addition, an FRT-flanked neomycin selection cassette and loxP site were inserted upstream of exon 3 and a second loxP site was inserted downstream of mutated exon 4. The selection cassette was removed via flp-mediated recombination and cre-mediated recombination deleted exons 3 and 4. Real-time PCR confirmed absence of mRNA in skin. (J:282272)