BRCA1 and obesity due to melanocortin 4 receptor deficiency: Regarding obesity, studies conducted with unselected populations have shown the opposite effect as those conducted with BRCA1/2 carriers; pre-menopause obesity protects against BC, whereas post-menopause obesity is a risk factor (Karoline B Kuchenbaecker K. B. et al., 2017; Lammert et al., 2018; Manchanda and Menon, 2018; Gallagher et al., 2020; Gao et al., 2021).