Common apolipoprotein E gene mutations contribute to lipoprotein glomerulopathy in China

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.

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.

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.

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.