Hypovitaminosis D in a Young Lebanese Population: Effect of GC Gene Polymorphisms on Vitamin D and Vitamin D Binding Protein Levels

Abstract

Bioactive vitamin D is a steroid hormone transported in blood via the vitamin D binding protein (DBP). Our study aimed to investigate the vitamin D status in a young Lebanese population and study the association of hypovitaminosis with levels of DBP. Polymorphisms in the GC gene that encodes DBP were also screened. Blood samples were collected from 179 university students. Vitamin D status and DBP levels were assayed by enzyme-linked immunosorbent assay (ELISA). DNA was extracted from 128 participants, and genotyping of the two GC gene SNPs, rs7041, and rs4588, was carried out by restriction fragment length polymorphism. Forty-seven percent of participants had hypovitaminosis D (<20 ng/ml). A significant positive correlation was observed between vitamin D status and DBP. Genotyping data showed that participants carrying the rs7041 GG and rs4588 AA genotypes had higher concentrations of DBP than those carrying other genotypes. Four allelic versions of the GC gene were observed, one of which, GC*3, was encountered for the first time in this study, and was found to be associated with both normal vitamin D and high DBP levels. Modifying genes such as GC could therefore affect DBP levels, and contribute, along with environmental factors, to the hypovitaminosis D observed in sunny countries.

GC Gene Polymorphisms and Vitamin D-Binding Protein Levels Are Related to the Risk of Generalized Aggressive Periodontitis

“…Medlej-Hashim et al collected blood samples from 128 university students and found participants with genotypes rs4588 AA had higher concentrations of DBP in a young Lebanese population [44]. The result was similar to ours.…”

Vitamin D Levels in Lebanese Patients with Schizophrenia: A Case-Control Study

“…Furthermore, our results indicated that patients with schizophrenia, as well as the healthy ones, had a vitamin D deficiency, similar to previous studies [2,4,36,37,40,41]. Other studies conducted in Lebanon had shown a hypovitaminosis D in the healthy population [35,[42][43][44][45].…”

“…We couldn't detect any association between the total PANSS score and its three subscales with vitamin D deficiency (p>0.05). Lebanon has a high prevalence of 25(OH)-D deficiency in adults and older adults [23,24] however, data regarding vitamin D levels in psychiatric patients is still lacking. Therefore, the primary objective of this study was to compare the vitamin D status in schizophrenics to that of healthy controls; secondary objectives were to assess the…”

The GC2 haplotype of the vitamin D binding protein is a risk factor for a low plasma 25-hydroxyvitamin D concentration in a Han Chinese population

“…No differences in the VDBP concentrations were found using polyclonal antibody method [37] or the LC-MS/MS method [19, 38], though the ELISA method with a monoclonal antibody for VDBP may induce bias [38–42]. Using an ELISA kit with a polyclonal antibody, we did not find a difference in the plasma VDBP concentrations between the subgroups of participants (Table 1 and Additional file 1: Table S1), nor was the VDBP concentration correlated with the plasma 25OHD concentration (Additional file 1: Table S3).…”