Identification and characterization of human GDF15 knockouts.

Growth differentiation factor 15 (GDF15) is a secreted protein that regulates food intake, body weight and stress responses in pre-clinical models. The physiological function of GDF15 in humans remains unclear. Pharmacologically, GDF15 agonism in humans causes nausea without accompanying weight loss, and GDF15 antagonism is being tested in clinical trials to treat cachexia and anorexia. Human genetics point to a role for GDF15 in hyperemesis gravidarum, but the safety or impact of complete GDF15 loss, particularly during pregnancy, is unknown. Here we show the absence of an overt phenotype in human GDF15 loss-of-function carriers, including stop gains, frameshifts and the fully inactivating missense variant C211G. These individuals were identified from 75,018 whole-exome/genome-sequenced participants in the Pakistan Genomic Resource and recall-by-genotype studies with family-based recruitment of variant carrier probands. We describe 8 homozygous ('knockouts') and 227 heterozygous carriers of loss-of-function alleles, including C211G. GDF15 knockouts range in age from 31 to 75 years, are fertile, have multiple children and show no consistent overt phenotypes, including metabolic dysfunction. Our data support the hypothesis that GDF15 is not required for fertility, healthy pregnancy, foetal development or survival into adulthood. These observations support the safety of therapeutics that block GDF15.