An alanine to threonine substitution at amino acid 393 (p.A393T) was introduced in exon 8 along with an FRT-flanked neomycin resistance cassette 290 bp downstream of exon 8. The neomycin resistance cassette was removed via flp-mediated recombination. The A393T corresponds to human A391T missense variant that is associated with a variety of traits ranging from Parkinsons disease and neuropsychiatric disease to cardiovascular and metabolic diseases and Crohns disease. (J:299683)