Akademik Veri Yönetim Sistemi
INSAC Natural and Health Sciences (INHS-2020), İstanbul, Türkiye, 22 - 23 Mayıs 2020, ss.416-417, (Tam Metin Bildiri)
It has been demonstrated in many studies that individuals in our country have low vitamin D levels. Since only unconnected molecules can be taken into the cells, it is understood whether individuals who are thought to have low levels of vitamin D in their bodies are actually low when looking at free D vitamins. Many studies have demonstrated that vitamin D is common among the individuals in our country. In fact, it is determined that individuals who are supposed to have low levels of vitamin D in their bodies have really low levels of the bioavailable vitamin D when measured. Vitamin D binding protein (DBP) is the main protein in vitamin D transport, but it binds up to 99 % of the circulating vitamin D metabolites together with albumin. Since the affinity of albumin to 25(OH)D is lower than the affinity of DBP, it carries only 10 % of 25(OH)Din plazma. It is DBP that determines the amount of free vitamin D and binds 85 to 90 % of circulating 25(OH)D3. The polymorphisms in the Gc gene encoding DBP vary according to races. Two single nucleotide polymorphisms (SNPs), rs7041 and rs4588 found in Gc gene lead to constitute the different phenotypes (Gc1f, Gc1s and Gc2).
The aim of this study is to show that low levels of 25(OH)Dis due to the polymorphisms in DBP gene of individuals who were presumed to have vitamin D deficiency. A total of 51 white Turkish individuals who applied to hospital for check-up between February 2019 and May 2019 and who did not receive vitamin D supplements in the last two years were included in the study. Plazma 25(OH)Dlevels were determined by chemiluminescence microparticle immunassay method as well as liquid chromatography-mass spectrometry (LC-MS / MS) method, albumin concentration was measured by a colorimetric test, and DBP concentration was determined by quantikine human vitamin DBP immunoassay. Using isolated genomic DNA, genotyping for rs4588 and rs7041 single nucleotide polymorphisms (SNPs) was performed by real-time polymerase chain reaction.
Of the 27 individuals with rs4588 polymorphism and AC genotype, the total 25 (OH) D level of 13 individuals was above 20 ng / ml, while the free vitamin D of 19 individuals was above 2 pg / ml. Of the 23 individuals connected to the CC genotype, 11 individuals had a total 25 (OH) D level below 20 ng / ml, while 10 individuals had free vitamin D above 2 pg / ml.
Of the 16 individuals with polymorphism rs7041, GG genotype, the total 25 (OH) D level of 5 individuals was below 20 ng / ml, while the free vitamin D of 4 individuals was above 2 pg / ml. Of 25 individuals with a GT genotype, 15 individuals had a total 25 (OH) D level below 20 ng / ml, while 8 individuals' free vitamin D was above 2 pg / ml. Of the 10 individuals with TT genotype, 6 individuals had a total 25 (OH) D level below 20 ng / ml, while 4 individuals' free vitamin D was above 2 pg / ml.
The results of our study are compatible with the literature. In our country with 4 seasons of sun, the level of vitamin D may not be as low as it is really stated. The reliability of the test should be reevaluated based on these results.