Genome-wide association studies suggest that APOL1-environment interactions more likely trigger kidney disease in African Americans with nondiabetic nephropathy than strong APOL1-second gene interactions

Kidney Int. 2018 Sep;94(3):599-607. doi: 10.1016/j.kint.2018.03.017. Epub 2018 Jun 7.

Abstract

African Americans carrying two apolipoprotein L1 gene (APOL1) renal risk variants have a high risk for nephropathy. However, only a minority develops end-stage renal disease (ESRD). Hence, modifying factors likely contribute to initiation of kidney disease such as endogenous (HIV infection) or exogenous (interferon treatment) environmental modifiers. In this report, genome-wide association studies and a meta-analysis were performed to identify novel loci for nondiabetic ESRD in African Americans and to detect genetic modifiers in APOL1-associated nephropathy. Two African American cohorts were analyzed, 1749 nondiabetic ESRD cases and 1136 controls from Wake Forest and 901 lupus nephritis (LN)-ESRD cases and 520 controls with systemic lupus erythematosus but lacking nephropathy from the LN-ESRD Consortium. Association analyses adjusting for APOL1 G1/G2 renal-risk variants were completed and stratified by APOL1 risk genotype status. Individual genome-wide association studies and meta-analysis results of all 2650 ESRD cases and 1656 controls did not detect significant genome-wide associations with ESRD beyond APOL1. Similarly, no single nucleotide polymorphism showed significant genome-wide evidence of an interaction with APOL1 risk variants. Thus, although variants with small individual effects cannot be ruled out and are likely to exist, our results suggest that APOL1-environment interactions may be of greater clinical importance in triggering nephropathy in African Americans than APOL1 interactions with other single nucleotide polymorphisms.

Keywords: APOL1; African Americans; FSGS; GWAS; chronic kidney disease; gene-gene interaction.

Publication types

  • Meta-Analysis
  • Research Support, N.I.H., Extramural

MeSH terms

  • African Americans / genetics*
  • Apolipoprotein L1 / genetics*
  • Case-Control Studies
  • Disease Progression
  • Gene-Environment Interaction*
  • Genetic Predisposition to Disease
  • Genome-Wide Association Study
  • Humans
  • Kidney Failure, Chronic / genetics*
  • Kidney Failure, Chronic / pathology
  • Lupus Nephritis / genetics*
  • Lupus Nephritis / pathology
  • Polymorphism, Single Nucleotide

Substances

  • APOL1 protein, human
  • Apolipoprotein L1