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Bone Abstracts (2017) 6 OC4 | DOI: 10.1530/boneabs.6.OC4

ICCBH2017 Oral Communications (1) (26 abstracts)

25-hydroxyvitamin D response to antenatal cholecalciferol supplementation is associated with common vitamin D related genetic variants: findings from the MAVIDOS trial

Rebecca Moon 1, , Nicholas Harvey 1, , Cyrus Cooper 1, , Stefania D’Angelo 1 , Elizabeth Curtis 1 , Sarah Crozier 1 , Sian Robinson 1 , Nikki Graham 4 , John Holloway 4 , Nicholas Bishop 5 , Stephen Kennedy 6 , Aris Papageorghiou 6 , Inez Schoenmakers 7, , Robert Fraser 9 , Saurabh Gandhi 9 , Ann Prentice 7 , Hazel Inskip 1, & Kassim Javaid 10

1MRC Lifecourse Epidemiology Unit, Southampton, Hampshire, UK; 2Paediatric Endocrinology, University Hospital Southampton NHS Foundatio Trust, Southampton, Hampshire, UK; 3NIHR Southampton Nutrition Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, Hampshire, UK; 4Human Health and Development, Faculty of Medicine, University of Southampton, Southampton, Hampshrie, UK; 5Academic Unit of Child Health, Sheffield Children’s Hospital, University of Sheffield, Sheffield, UK; 6Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital, University of Oxford, Oxford, UK; 7MRC Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, UK; 8Department of Medicine, Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, Norfolk, UK; 9Sheffield Hospitals NHS Trust (University of Sheffield, Sheffield, UK; 10NIHR Musculoskeletal Biomedical Research Unit, University of Oxford, Oxford, UK.

Objectives: Single nucleotide polymorphisms (SNP) in genes related to vitamin D metabolism have been associated with 25-hydroxyvitamin D (25(OH)D) status, but these relationships have not been examined in pregnancy or following antenatal vitamin D supplementation. We assessed whether SNPs in DHCR7 (7-dehydrocholesterol reductase), CYP2R1 (25-hydroxylase), CYP24A1 (24-hydroxylase) and GC (Vitamin D binding protein) were associated with the response to antenatal vitamin D supplementation.

Methods: MAVIDOS is a randomised double-blind placebo-controlled trial of 1000IU/day cholecalciferol from 14 weeks gestation until delivery in women with a baseline 25(OH)D of 25–100 nmol/l. Anthropometry, serum 25(OH)D (Diasorin Liaison), health and diet were assessed at 14 and 34 weeks gestation. Genotyping of rs12785878 (DHCR7), rs10741657 (CYP2R1), rs6013897 (CYP24A1) and rs2282679 (GC) was undertaken by LGC Genomics (Hoddeston, UK) using KASP™ competitive allele-specific PCR. Multiple linear regression was performed using an additive model with the homozygous minor allele as the reference group (beta represents the change in outcome per additional major allele), adjusting for a number of previously identified determinants of 25(OH)D.

Results: 712 women (367 placebo, 345 cholecalciferol) were included (95.8% White ethnicity). Only rs12785878 (DHCR7) was associated with baseline 25(OH)D (β=4.1 nmol/l (95% CI 2.2, 6.1), P<0.001). Conversely, rs10741657 (CYP2R1) (β=−4.1 nmol/l (95%CI −7.1, −1.2), P=0.006) and rs2282679 (GC) (β=4.4 nmol/l (95%CI 1.2, 7.6), P=0.007) were associated with achieved 25(OH)D after supplementation, but rs12785878 and rs6013897 were not.

Conclusion: Genetic variation in DHCR7, which encodes 7-dehyrocholesterol reductase in the cholesterol/vitamin D biosynthesis pathway in the skin appears to modify baseline 25(OH)D, whereas the response to antenatal cholecalciferol supplementation was associated with SNPs in CYP2R1 and GC, which may alter 25-hydroxylase activity and vitamin D binding protein synthesis. Women with more risk alleles may require higher supplement doses to achieve vitamin D repletion in pregnancy.

Disclosure: The authors declared no competing interests.

Volume 6

8th International Conference on Children's Bone Health


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