Inherited hyperchylomicronaemia in the cat

Cats with inherited hyperchylomicronaemia show fasting hyperlipidaemia, lipaemia retinalis, xanthomata in a variety of tissues (skin, liver, kidney, etc), peripheral neuropathies and, in some kittens, anaemia. The peripheral nerve lesions result from compression by xanthomata. The fasting hyperlipidaemia is characterised by hypertriglyceridaemia with elevation of chylomicrons and often mild very low density lipoprotein elevation. Lipoprotein lipase (LPL) activity measured after heparin injection, is absent or reduced. In one family, a high concentration of enzyme mass is present and the cats produce an abnormal LPL enzyme protein which fails to bind to the vascular endothelium. The defect is inherited as an autosomal recessive trait. Molecular analyses have not identified any major structural rearrangement in the LPL gene, but it has been suggested that a point mutation is present in the heparin binding domain of the protein (of one affected family).