OXER1 and obesity due to melanocortin 4 receptor deficiency: Impaired lactation, affecting 1 in 20 women, is characterized by delayed lactogenesis or insufficient milk production, often influenced by maternal conditions such as obesity, diabetes, and thyroid dysfunction [87]. GWAS have identified genetic factors underlying breastfeeding traits, including SNPs in OXE1 (Oxoeicosanoid Receptor 1) gene, a receptor for polyunsaturated fatty acids found in breastmilk, and genes in the fatty acid desaturase family (FADS1, FADS2, FADS3) which influence breastmilk fatty acid composition and breastfeeding duration [88, 89].