VDR, SOD-2, and CYP24A1 Gene Expression in Different Genotypes of BsmI SNP of the Vitamin D Receptor Gene in Individuals with Hypovitaminosis.

BACKGROUND: Hypovitaminosis D is a public health problem due to its implications for various diseases. Vitamin D has numerous functions, such as modulating the metabolism of cellular tissues, and it is expressed through the vitamin D receptor (VDR) gene that may influence gene expression modulation, which plays an important role in vitamin D metabolism. OBJECTIVE: To evaluate the effect of the genotypes of BsmI single nucleotide polymorphism (SNP) of the VDR gene on VDR, SOD2, and CYP24A1 gene expression in individuals with low serum vitamin D levels. METHODS: This was a cross-sectional analytical study. After signing the informed consent form, individuals were invited to participate and answered a structured questionnaire with identification data. Blood was collected for biochemical analysis, and vitamin D was measured by chemiluminescence; BsmI polymorphism was determined using real-time polymerase chain reaction (PCR) assays with TaqMan allelic discrimination, and gene expression was conducted by qRT-PCR using QuantiFast SYBR® Green PCR Master Mix. Data were analyzed using the SPSS 20.0 software, and differences were considered significant at p < 0.05. RESULTS: 98 individuals with vitamin D ≤ 20 ng/dL were evaluated, and the BsmI SNP of the VDR gene showed CYP24A1 overexpression and low SOD2 expression. CONCLUSION: BsmI SNP of the VDR gene can modulate the expression of the genes evaluated without interfering with serum levels.

Black skin color but not VDR gene represent a risk factor for low serum levels of vitamin D in self-declared black individuals.

BACKGROUND: The absorption of vitamin D occurs via two main pathways: first, through the biosynthesis in the skin under the exposure of UV from sunlight; and second, through the intake of certain foods. However, its levels can be influenced by both genetic and environmental factors, which can generate changes such as vitamin D deficiency (hypovitaminosis D), a condition that black adults have a high potential to suffer from. OBJECTIVE: The aim of this work is to study the association of skin color (self-reported: black, brown and white), food consumption, and the BsmI polymorphism in the vitamin D receptor gene (VDR) on serum levels of vitamin D in a group of adults. METHODS: This was a cross-sectional analytical study. Individuals in the community were invited to participate in the research and, After signing the informed consent, a structured questionnaire was applied containing identification data, self-declaration of race/color, and nutritional data (Food frequency questionnaire (FFQ) and 24 h); afterwards, blood was collected for biochemical analysis, vitamin D was measured by Chemiluminescence and RT-PCR was used to evaluate the BsmI polymorphism of the VDR gene. Data was analyzed using a statistical program (SPSS 20.0) and differences between groups using p < 0.05. RESULTS: A total of 114 persons was evaluated between black, brown and white individuals. It was found that a large part of the sample presents hypovitaminosis D, and blacks stand out with an average serum vitamin D level of 15.9 ng/dL. The group demonstrated that dietary intake of vitamin D is low, with the present study is a pioneer in associating the polymorphism of the VDR gene (BsmI) with the consumption of foods that are considered to have a higher content of vitamin D in their composition. CONCLUSION: The VDR gene does not represent a risk factor for the consumption of vitamin D in this sample, and it was found that the self-declaration of "black" skin color was an independent risk factor for low serum levels of vitamin D.