FP31-2 Variations in the vitamin D binding protein (DBP) gene are related to lower 25-hydroxyvitamin D levels in healthy girls: a cross-sectional study

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: FP31-Disorders of Vitamin D Metabolism & Action
Monday, June 17, 2013: 10:45 AM-11:15 AM
Presentation Start Time: 10:50 AM
Room 130 (Moscone Center)

Poster Board MON-243
Betânia Rodrigues Santos*1, Luis P G Mascarenhas2, Margaret Christina da Silva Boguszewski3 and Poli Mara Spritzer4
1Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil, 2Universidade Federal do Paraná, Curitiba, Brazil, 3Federal University of Parana, Curitiba, Brazil, 4Univ Fed do Rio Grande do Sul, Porto Alegre RS, Brazil
Vitamin D deficiency has been recognized as a worldwide epidemic, affecting several pediatric and adolescent populations. We determined the genotype and haplotype distribution of the rs4588 and rs7041 polymorphisms of the GC gene encoding vitamin D binding protein (DBP) and investigated the associations between these gene variants and their haplotypes with 25-hydroxyvitamin D [25(OH)D] levels in girls from South Brazil. Cross-sectional study including 198 apparently healthy girls aged 10 to 18 years. Height and weight were measured for calculation of body mass index (BMI) percentiles for age. Plasma levels of 25(OH)D were assessed by radioimmunoassay and 25(OH)D status was classified as sufficient (≥ 30 ng/mL), insufficient (20-29.9 ng/mL) or deficient (< 20 ng/mL). Samples were then stored with identification of the season of blood collection (spring/summer and fall/winter). Participants were genotyped for rs4588 (change of the C→A) and rs7041 (change of the T→G) by real-time PCR, with allelic discrimination assays. Mean chronological age and BMI percentile were 13.17 ± 1.74 years and 57.81 ± 29.03, respectively. Sufficient circulating 25(OH)D levels (≥ 30 ng/mL) were found in 9.1% of the overall group, insufficient levels (20-29.9 ng/mL) in 59.6%, and deficient levels (< 20 ng/mL) in 31.3%. Genotype frequencies were CC = 54.5%, CA = 37.4%, and AA = 8.1% for rs4588; TT = 28.3%, TG = 46.5%, and GG = 25.3% for rs7041. The rs4588 polymorphism was in linkage disequilibrium with the rs7041 polymorphism (|D’| = 1; r2 = 0.38). The AA genotype of rs4588, TT genotype of rs7041 and CT-AT/AT-AT (GC 1f-2/2-2) diplotypes were significantly associated with lower 25(OH)D levels, even after adjustment for age and season at the time of blood collection. The GC gene genotype may be related to the susceptibility to low 25(OH)D levels in female children and adolescents.

Nothing to Disclose: BRS, LPGM, MCDSB, PMS

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: National Institute of Hormones and Women’s HealthHospital de Clínicas de Porto Alegre - FIPE