ERBB4 and Obesity: Common PCOS-associated variants linked to genes, such as thyroid adenoma-associated protein (THADA), insulin receptor (INSR), follicle-stimulating hormone receptor (FSHR), ERBB4 receptor tyrosine kinase 4 gene (ERBB4), and DENN domain containing 1 A (DENND1A), confer mostly obesity-related metabolic risk, IR, impaired folliculogenesis, and abnormal androgen biosynthesis [68–72].