Gene discovery for high-density lipoprotein cholesterol level change over time in prospective family studies

Backgrounds and aims: Several genes are known to contribute to the levels and metabolism of HDL-C, however, their protective effects in cardiovascular disease (CVD), healthy aging, and longevity are complex and poorly understood. It is also unclear if these genes predict longitudinal HDL-C change. We aimed to identify loci influencing HDL-C change. Methods: We performed a genome-wide association study (GWAS) with harmonized HDL-C and imputed genotype in three family-based studies recruited for exceptional survival (Long Life Family Study), from community-based (Framingham Heart Study) and enriched for CVD (Family Heart Study). In 7738 individuals with at least 2 visits, we employed a growth curve model to estimate the random linear trajectory parameter of age-sex-adjusted HDL-C for each person. GWAS was performed using a linear regression model on HDL-C change accounting for kinship correlations, population structure, and differences among studies. Results: We identified a novel association for HDL-C with GRID1 (p = 5.43 x 10(-10)), which encodes a glutamate receptor channel subunit involved in synaptic plasticity. Seven suggestive novel loci (p < 1.0 x 10(-6); MBOAT2, LINC01876-NR4A2, NTNG2, CYSLTR2, SYNE2, CTXND1-LINC01314, and CYYR1) and a known lipid gene (ABCA10) showed associations with HDL-C change. Two additional sex-specific suggestive loci were identified in women (DCLK2 and KCNJ2). Several of these genetic variants are associated with lipid-related conditions influencing cardiovascular and metabolic health, have predictive regulatory function, and are involved in lipid-related pathways. Conclusions: Modeling longitudinal HDL-C in prospective studies, with differences in healthy aging, longevity and CVD risk, contributed to gene discovery and provided insights into mechanisms of HDL-C regulation.