1 Pediatric Department, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
2 Diagnostic Radiology Department, Faculty of Medicine, Suez Canal University, Ismailia, Egypt.
3 Genetics Unit, Histology and Cell Biology Department, Faculty of Medicine, Suez Canal University, Ismailia, Egypt.
4 Department of Surgery, Tulane University, School of Medicine, New Orleans, Louisiana, USA.
5 Clinical Pathology Department, Faculty of Medicine, Suez Canal University, Ismailia, Egypt.
6 Medical Biochemistry and Molecular Biology Department, Faculty of Medicine, Suez Canal University, Ismailia, Egypt.
7 Biochemistry Department, Faculty of Medicine, Northern Border University, Arar, Saudi Arabia.
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The reduced rate of bone formation despite the availability of vitamin
D has been reported in β-thalassemia. Genetic factors, together with
environmental ones, could be implicated in this condition. Since
vitamin D binding protein (VDBP) maintains bioavailability of vitamin D
which binds to vitamin D receptor (VDR)-retinoid X receptor alpha
(RXRA) heterodimer to exert its molecular actions, we speculated that
vitamin D metabolic-axis expression signature and variants could be
potential molecular candidates for bone turnover/disease in
thalassemia. To this end, this study aims to analyze VDR/RXRA expression signature, and two VDBP variants in a pilot sample of Egyptian β-thalassemia children in correlation with bone mineral density (BMD).
Patients nd Methods
|Table 1. The designed primers using Primer3 and UCSC genome browser.|
|Table 2. The baseline characteristics and biochemical profile of thalassemia children and controls..|
|Figure 1. .Expression profile of VDR and RXRA in β-thalassemia patients and controls. Values are presented as medians. The box defines upper and lower quartiles (25% and 75%, respectively) and the error bars indicate upper and lower adjacent limits. Vitamin D was measured by ELISA, while gene expression was quantified using Real-Time PCR. Fold-change was normalized to GAPDH and calculated using the delta-delta CT method [= 2 (-ΔΔCT)] compared to controls with relative expression at 1.0. Mann-Whitney U test was used. Statistically significant at P value < 0.05.|
|Table 3. The genotype analysis of VDBP polymorphisms.|
|Table 4. Association of VDBP variants with clinical data in β-thalassemia patients.|
|Figure S1 Some results of lumbar spine Dual-energy X-ray absorptiometry (DEXA) for study pediatric β-thalassemia cases. A patient no. 5 (male; 6 year-old), B patient no. 17 (male; 7 year-old), C patient no. 28 (female; 15 3/12 year-old), D patient no. 34 (female; 8 year-old).|
|Figure S2. Association of VDBP polymorphisms (rs 7041 and rs4588) with biochemical data in pediatric β-Thalassemia cases. Kruskal Wallis test followed by Dunn's multiple comparison tests were used.|