Nucleotide substitutions in exon 7 result in the amino acid substitution of asparagine for aspartic acid at position 212 (D212N). A floxed neo cassette was inserted downstream of the modified exon 7. Cre-mediated recombination removed the neo cassette and allowed for expression of the knock-in transcript. The knock-in product is caspase-cleavage deficient. (J:171914)