This phenotypic mutation was identified in a screen of the progeny of ENU treated male mice for serum cholesterol elevation in response to a high fat, high cholesterol diet. It is a G to A transition at nucleotide 2096 of the mouse cDNA sequence, in a region encoded by exon 14, resulting in replacement of a highly conserved cysteine by tyrosine at amino acid 699 (C699Y; count includes 21-aa signal peptide), which is predicted to cause a folding defect and failure of the protein to transit from the endoplasmic reticulum to the Golgi system. (J:140060)