FNIP1 variants are associated with favourable metabolism in 1 million humans

) that are enriched for liver- and adipose-expressed master regulators of energy balance, storage and metabolism; 23 (39%) of these genes encode approved or clinical-stage drug targets. Ultra-rare protein-truncating variants in FNIP1 (allele frequency, 0.01%), which encodes a suppressor of energy expenditure and mitochondrial metabolism, are associated with a lower TG:HDL ratio, lower liver fat, lower glycaemia, favourable fat distribution and around 60% lower odds of cardiometabolic disease. FNIP1 knockdown in primary human hepatocytes induces lipid breakdown and lysosomal gene expression, while combined hepatic knockdown of Fnip1 with its paralogue Fnip2 or knockdown of its interactor Flcn protect against weight gain, reduce liver fat and enhance insulin sensitivity in mice fed a high-fat diet. Our study implicates the FNIP1 pathway in human energy metabolism and highlights its inhibition as a potential therapeutic strategy in cardiometabolic disease.