Calcitriol Reverses the Down-Regulation Pattern of Tuberous Sclerosis Complex Genes in an In Vitro Calcification Model

Tuberous sclerosis complex (TSC) is a neurocutaneous syndrome with autosomal dominant inheritance, and most of the cases are related to loss of function of the TSC1 and TSC2 genes. TSC may occur with a wide range of clinical findings and skin, kidney, brain, and heart are the most commonly affected organs. Brain calcifications in TSC are also described and reported as diffuse and without pattern of symmetry or bilaterality. Recently, a new discovery opened the possibility of using vitamin D (VitD) for treating cerebral calcifications. Calcitriol, the active form of VitD, was able to reduce the calcification in an in vitro model, increasing expression of a gene related to primary familial brain calcification. We show that in the same experimental model, calcitriol was also able to restore and even increase expression of genes related to TSC. This article discusses the use of calcitriol supplementation in patients with TSC, which can be a very interesting strategy due to its low cost and because it is already used in various therapies.