Loss-of-function of MFGE8 and protection against coronary atherosclerosis

Cardiovascular diseases are the leading cause of premature death and disability worldwide, with both genetic and environmental determinants. While genome-wide association studies have identified multiple genetic loci associated with cardiovascular diseases, exact genes driving these associations remain mostly uncovered. Due to Finlands population history, many deleterious and high-impact variants are enriched in the Finnish population giving a possibility to find genetic associations for protein-truncating variants that likely tie the association to a gene and that would not be detected elsewhere. In FinnGen, a large Finnish biobank study, we identified an inframe insertion rs534125149 in MFGE8 to have protective effect against coronary atherosclerosis (OR = 0.75, p = 2.63x10-16) and related endpoints. This variant is highly enriched in Finland (70-fold compared to Non-Finnish Europeans) with allele frequency of 3% in Finland. The protective association was replicated in meta-analysis of biobanks of Japan and Estonian (OR = 0.75, p = 5.41x10-7). Additionally, we identified a splice acceptor variant rs201988637 in MFGE8, independent of the rs534125149 and similarly protective in relation to coronary atherosclerosis (OR = 0.72, p = 7.94x10-06) and related endpoints, with no significant risk-increasing associations. The protein-truncating variant was also associated with lower pulse pressure, pointing towards a function of MFGE8 in arterial stiffness and aging also in humans in addition to previous evidence in mice. In conclusion, our results show that inhibiting the production of lactadherin could lower the risk for coronary heart disease substantially.