Common Apolipoprotein E Gene Mutations Contribute to Lipoprotein Glomerulopathy in China

Abstract

Background: Lipoprotein glomerulopathy (LPG) is a unique disease characterized by thrombus-like lipoprotein deposition in glomeruli and an increased serum apolipoprotein E level (ApoE protein or APOE gene). Several APOE mutations contribute to the occurring of LPG. Methods: We confirmed LPG in 7 individuals by renal biopsy, and investigated families of 2 patients with urinalysis, serum creatinine and serum lipid examination. Exons of APOE of all individuals as well as their relatives were amplified and sequenced directly. Results: Two types of APOE mutations were identified in the 7 patients and their relatives. APOE Maebashi (Arg142-Leu144→0) heterozygotes were found in 5 individuals who were from 4 different families. APOE Kyoto (Arg25-Cys) was confirmed heterogeneous in another 2 individuals. Both mutations present incomplete penetrance. Conclusion: Our research indicates that APOE Maebashi (Arg142-Leu144→0) is a common mutation in Chinese LPG. However, not all carriers of the 2 mutations have LPG, although hyperlipidemia and high serum ApoE level are tested. There are likely other reasons, such as a local mechanism in the glomeruli, which participated in the renal injury.