Genetic variation of apolipoprotein E does not contribute to the lipid abnormalities secondary to childhood minimal change nephrotic syndrome

Minimal change nephrotic syndrome (MCNS) is a common progressive renal disorder occurring in childhood that is characterized by alterations of permselectivity at the glomerular capillary wall, resulting in its inability to restrict the urinary loss of protein. Hyperlipidemia (HLP) is not only an important clinical manifestation of MCNS but is also involved in cardiovascular disease and in progressive renal damage. ApoE is a polymorphic protein. Besides modulation of lipid metabolism, apoE can also elevate the sulfate-proteoglycan in glomerular filtration membrane and inhibit the proliferation of mesengial cells. The present study aimed mainly to determine whether genetic polymorphism of apoE is involved in the HLP secondary to childhood MCNS. Genomic DNA was extracted from 250 children diagnosed with MCNS and 200 healthy controls. ApoE genotype was determined by PCR-restriction fragment length polymorphism (RFLP) analysis. The fasting serum lipoprotein (a) [Lp(a)], total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein A1 (apoA1), and apoB were measured. Serum concentrations of Lp(a), TC, TG, HDL-C, nonHDL-C, LDL-C, and apoB were higher in the MCNS than in the control group (P < 0.05). No significant differences in genotypes and alleles frequencies were observed for the apoE Hha I restriction sites in MCNS patients as compared to controls (P > 0.05). No significant differences in serum lipid levels were observed for variant genotypes and alleles of apoE Hha I restriction site in both MCNS and healthy children (P > 0.05). Genetic variation of apoE does not contribute to the lipid abnormalities secondary to childhood MCNS.