A mutation in the lipoprotein lipase gene is the molecular basis of chylomicronemia in a colony of domestic cats

Members of a domestic cat colony with chylomicronemia share many phenotypic features with human lipoprotein lipase (LPL) deficiency. Biochemical analysis reveals that these cats do have defective LPL catalytic activity and have a clinical phenotype very similar to human LPL deficiency, To determine the molecular basis underlying this biochemical phenotype, we have cloned the normal and affected cat LPL cDNAs and shown that the affected cat has a nucleotide change resulting in a substitution of arginine for glycine at residue 412 in exon 8. In vitro mutagenesis and expression studies, in addition to segregation analysis, have shown that this DNA change is the cause of LPL deficiency in this cat colony. Reduced body mass, growth rates, and increased stillbirth rates are observed in cats homozygous for this mutation. These findings show that this LPL deficient cat can serve as an animal model of human LPL deficiency and will be useful for in vivo investigation of the relationship between triglyceride rich lipoproteins and atherogenic risk and for the assessment of new approaches for treatment of LPL deficiency, including gene therapy.