A CGG to TGA change resulting in an arginine to stop codon change at amino acid 368 (p.R368*) was introduced in exon 12 and a floxed neomycin cassette was inserted upstream of exon 12. The selection cassette was removed via cre-mediated recombination. This nonsense mutation has been identified in patients with type 1 acrodysostosis. (J:303060)