CPT1A and obesity due to melanocortin 4 receptor deficiency: Cheshmeh et al., in a case-control study involving 150 infants, aged between 5 and 6 months, investigated the impact of breastfeeding and formula feeding on the expression of obesity-related genes, which are fat mass and obesity-associated (FTO), carnitine palmitoyltransferase 1A (CPT1A), and peroxisome proliferator-activated receptor-α (PPAR-α).