THU648 Free Vitamin D And Rs7041 Polymorphism In Vitamin D Binding Protein Gene In Policystic Ovary Syndrome
Authors: Amelia Maidana Patricia Nieves , Gutierrez Guillermo Andres , Rojo Mailén , Fernández Gladys Isabel , Gonzalez Diego , Aparicio Vanesa , D'Isa Estela , Demayo Sandra , Maggi Liliana , Fabre Bibiana Raquel , Cerrone Gloria Edith , Mesch Viviana 
Published: October 2023

Abstract
Disclosure: P.N. Maidana: None. G.A. Gutierrez: None. M. Rojo: None. G.I. Fernández: None. D. Gonzalez: None. V. Aparicio: None. E. D'Isa: None. S. Demayo: None. L. Maggi: None. B.R. Fabre: None. G.E. Cerrone: None. V. Mesch: None.
Introduction: Polycystic ovary syndrome (PCOS) is related with an increased risk of developing metabolic complications, such as vitamin D (VitD) deficiency, which could be in turn associated with insulin resistance and other metabolic risk factors. Most (85-90%) of the circulating VitD is bound to its specific carrier protein (DBP), with a smaller amount (10-15%) bound to albumin and less than 1% exists in a free form, which is the biologically active fraction. So, it should be more useful to determine Free VitD to asses VitD status. Aditionally, the influence of genetic factors on serum VitD levels must be taken into account, such as single nucleotide polymorphisms (SNPs) in the DBP gene, as rs7041 and rs4588. We previously found correlations between VitD and different hormonal and metabolic parameters in PCOS women. In this study our aim is to evaluate if measuring Free VitD in PCOS women gives more information than total VitD, and subsequently, to determine the frequency of SNP rs7041 in the DPB gene.
Subjects and methods: 104 women (19-41 years) with PCOS and 64 healthy controls (22-45 years) were initially recruited. In a subgroup of 37 patients and 24 controls, Free VitD was measured by ELISA; in all of them body mass index (BMI) was calculated, waist circumference (WC) was measured as indicator of abdominal obesity, VitD and SHBG were measured by chemiluminescence, triglycerides (TG) and HDL cholesterol (HDL-chol) were determined by enzymatic colorimetric method, total testosterone (To) by electrochemiluminescence and free To (FTo) was calculated from To and SHBG. TG/HDL-chol and Lipid accumulation product (LAP) indexes were calculated, as secondary markers of insulin resistance. The rs7041 variant genotyping was performed in 27 PCOS patients and 27 controls, by PCR real time with TaqMan probes in peripheral blood leucocytes. Statistical analysis was performed by SPSS 22 software.
Results: BMI, WC, To, FTo, TG/HDL-chol and LAP were significantly higher in PCOS than controls, while VitD was lower. Free VitD showed no significant differences between patients and controls. VitD levels showed negative correlations with BMI, WC, To, FTo, TG/HDL-chol and LAP. Free VitD only showed a positive correlation with total VitD.No statistical differences in genotype frequencies were observed between patients and controls. Genotype and allelic frequencies analysis could not be performed due to the high presence of heterozygosity in both groups.
Conclusions: The fact that we found significant differences between total VitD levels in PCOS and controls but not in Free VitD could be attributed to differences in DBP. The lack of correlations between Free Vit D and the different parameters analyzed suggests that measuring Free VitD in PCOS would not have advantages with respect to total VitD.Variant genotyping analysis must be extended to a larger number of individuals and also other variants could be studied.
Presentation: Thursday, June 15, 2023