A case of hyperlipidemia with homozygous apolipoprotein E5 (Glu~3→Lys)

摘要

In this study, we present clinical feature of a novel case with homozygous apolipoprotein (apo) E5. The patient was a 53-year-old Japanese woman. She was from a small island off the coast of Kagoshima Prefecture, Japan. Her parents wee first degree cousins. No corneal opacification, xanthomatosis, lymphadenopathy, or hepatosplenomegaly was observed. There have been no signs of clinically overt atherosclerosis to data. Her serum total cholesterol, triglycerides (TG) and high-density lipoprotein (HDL)-cholesterol levels were 11.6, 6.1 and 1.2 mmol/l, respectively, and apo A-I, A-II, B, C-II, C-III and E levels were 121, 34.8, 269, 10.4, 25.7 and 10.3 mg/dl, respectively. Serum lipoprotein profile analyzed by agarose gel electrophoresis and differential staining revealed markedly increased cholesterol and TG in both β and preβ-migrated lipoproteins, whereas α-migrated lipoprotein showed decreased cholesterol. Her apo E isoform analyzed by isoelectric focusing (IEF) was found to be homozygous apo E5. Polymerase chain reaction restriction fragment length polymorplhism (PCR-RFLP) analysis of her apo E and lipoprotein lipase (LPL) genes revealed that shed had a homozygous apo E (Glu~3 → Lys) and heterozygous LPL variant Ser~(447) to Ter. Her son and daughter, both of whom had hyperlipidemia, were found to have apo E3/5 phenotype. Direct sequencing analysis of her apo E gene confirmed a homozygous one nucleotide change: G to A at nucleotide position of 2836 in the exon 3, resulting in Glu~3→Lys mutation. This is the first report of lipids and lipoprotein profiles in patients with homozygous apo E5 (Glu~3→Lys).