Studies in mice model demonstrated that VDR and 1a-hydroxylase knockout mice had VD3 deficiency and reduced circulating calcium levels as well as the impairment of spermatogenesis, along with a significant decreasing in both the number and motility of sperm in comparison to the wild-type group [70, 72]. This evidence concerns the gene VDR and hyperinsulinemic hypoglycemia, familial, 4.