GJA1 and obesity due to melanocortin 4 receptor deficiency: It is noteworthy that obesity was shown to trigger breast adipose tissue inflammation, leading to increased risk of breast cancer [48, 49], and has been associated with loss of the apical distribution of Cx43 in 3D cultures of S1 breast epithelial cells, mitotic spindle orientation (MSO), and induced proliferation and multilayering in S1 acini [19, 21].