GAS6 and obesity due to melanocortin 4 receptor deficiency: Furthermore, mutations of GAS6 were shown to be associated with obesity and type 2 diabetes individuals [57] and its serum levels were positively associated with testosterone levels in male patients with coronary heart disease [58], and androgen could directly regulate GAS6 expression by binding the androgen-response elements of its promoter regions for inhibition of vascular calcification [59].