A young type III hyperlipoproteinemic patient associated with apolipoprotein E deficiency.

A 13-year-old female patient had noticed tuberoeruptive xanthomas since 3 years of age. Her serum, VLDL, and IDL cholesterol levels were high (348, 158, and 60 mg/dL, respectively), while LDL and HDL cholesterol levels were 56 and 62 mg/dL, respectively. VLDL-cholesterol/serum triglyceride ratio was extremely high (0.86), suggesting type III hyperlipoproteinemia (HLP). Her apo E was undetectable by the single radial immunodiffusion studies and SDS-polyacrylamide gel electrophoresis. Her parents showed hypertriglyceridemia and her two siblings were normolipidemic, and their apo E levels were normal. Genomic DNA digested with BamHI or EcoRI did not show gross differences in the restriction fragment length between the apo-E-deficient patient and normal controls. Thus, apo E deficiency may be characterized by early appearance of clinical manifestations of type III HLP and higher VLDL-cholesterol/serum triglyceride ratio.