Association of Vitamin D3 Receptor Gene and Biochemical Parameters in Iraqi Gestational Diabetic Patients

Abstract

Gestational diabetes mellitus (GDM) is defined as glucose intolerance of variable severity that occurs during pregnancy . Women with GDM represent a heterogeneous group .GDM is characterized by pancreatic β cell function that is insufficient to meet body insulin needs , probably due to autoimmune diseases , insulin resistance or genetic abnormalities . The prevalence of GDM may range from 1 to 14% of all pregnancies. Diagnosis of GDM is by using a two - hour OGTT with a 75 g dose of glucose . This study aims to examine concentrations of 25 (OH) vitamin D in Iraqi women with normal pregnancies and pregnancies complicated by GDM , and with two single nucleotide polymorphism (SNP A/G rs # 1544410 and SNP C/T rs # 10735810 in vitamin D receptor (VDR) to the susceptibility to gestational diabetes in the Iraqi women , The second aim of this study is to investigate the association of VDR together with 25-hydroxy vitamin D serum levels, and biochemical parameters (Fasting Blood Glucose, Glycated Hemoglobin, Insulin hormone, Insulin Resistance, Parathyroid Hormone, Insulin Like Growth Factor Hormone, Calcium ion , Phosphorus ion and lipid profile . This cross-sectional study was carried out at Ramadi Teaching Hospital for gynecology and pediatrics ,office Wahj Al-DNA scientific and Al-Mawla laboratory for media lab during the period from 1 st September 2017 to the end of April 2018. It involved 40 cases pregnant with GDM, 30 cases pregnant without GDM and 30 cases with normal vitamin D and non pregnant to represent the control group . III A venous blood samples were collected at morning after fasting for 10-12 hours. The blood samples were divided into two aliquots, 2 ml were transferred into EDTA for HbA1c and DNA extraction, and 3 ml used for laboratory investigation . The mean of serum vitamin D concentrations was lower in both groups: pregnant with GDM (6.83 ± 3.547ng/ml) and pregnant without GDM (8.73±4.158 ng/ml) and there was no significant differences between these groups but there was significant differences in concentrations of FBG, HbA1c, insulin hormone, HOMA-IR, lipid profile except of high density lipoprotein cholesterol, parathyroid hormone and calcium ion between normal pregnant and gestational pregenant. There was no significant differences in concentrations in insulin – like growth factor hormone and phosphorus ion . Vitamin D had a significant negative correlation with HOMA-IR (p < 0.014) in pregnant with GDM The results showed a relationship between age and GDM (p < 0.001) and also between body mass index and GDM (p < 0.001) . Vitamin D receptor rs (10735810) and rs (1544410) polymorphisms were not associated with Iraqi gestational dibetes mellitus. Homozygous CC and homozygous GG turned out to be as a preventive genotype of gestational diabetes mellitus (OR < 1) while CT ,TT and GA turned out to be related with risk of GDM (OR ≥1).The allele C and allele G represent as a preventive allele (preventive factor) , while the allele T and allele A act as etiological factor.