Besides albumin, vitamin D binding protein (DBP), also known as GC-globulin, binds to all vitamin D metabolites, creating a large pool of circulating 25-hydroxyvitamin D (25(OH)D3) and 1,25-dihydroxyvitamin D (1,25(OH)2-D3), which helps balance bone metabolism and prevent rapid vitamin D deficiency. The gene discussed is GC; the disease is vitamin D deficiency.