Genotypes associated with lipid metabolism contribute to differences in serum lipid profile of GH-deficient adults before and after GH replacement therapy

Abstract

ObjectiveGH deficiency (GHD) in adults is associated with an altered serum lipid profile that responds to GH replacement therapy (GHRT). This study evaluated the influence of polymorphisms in genes related to lipid metabolism on serum lipid profile before and after 1 year of GHRT in adults.Design and methodsIn 318 GHD patients, total cholesterol (TC) serum concentrations, LDL-C, HDL-C, and triglycerides (TG) were assessed. Using a candidate gene approach, 20 single nucleotide polymorphisms (SNPs) were genotyped. GH dose was individually titrated to obtain normal serum IGF1 concentrations.ResultsAt baseline, the minor alleles of cholesteryl ester transfer protein (CETP) gene SNPs rs708272 and rs1800775 were associated with higher serum TC and apolipoprotein E (APOE) gene SNP rs7412 with lower TC concentrations;CETPSNPs rs708272, rs1800775, and rs3764261 and apolipoprotein B (APOB) gene SNP rs693 with higher serum HDL-C;APOESNP rs7412, peroxisome proliferator-activated receptor gamma (PPARG) gene SNP rs10865710 with lower LDL-C, andCETPSNP rs1800775 with higher LDL-C; andAPOE/C1/C4/C2cluster SNP rs35136575 with lower serum TG. After treatment,APOBSNP rs676210 GG genotype was associated with larger reductions in TC and LDL-C andPPARGSNP rs10865710 CC genotype with greater TC reduction. All associations remained significant when adjusted for age, sex, and BMI.ConclusionsIn GHD adults, multiple SNPs in genes related to lipid metabolism contributed to individual differences in baseline serum lipid profile. The GH treatment response in TC and LDL-C was influenced by polymorphisms in theAPOBandPPARGgenes.