Low-Frequency Synonymous Coding Variation in CYP2R1 Has Large Effects on Vitamin D Levels and Risk of Multiple Sclerosis

Am J Hum Genet. 2017 Aug 3;101(2):227-238. doi: 10.1016/j.ajhg.2017.06.014. Epub 2017 Jul 27.

Abstract

Vitamin D insufficiency is common, correctable, and influenced by genetic factors, and it has been associated with risk of several diseases. We sought to identify low-frequency genetic variants that strongly increase the risk of vitamin D insufficiency and tested their effect on risk of multiple sclerosis, a disease influenced by low vitamin D concentrations. We used whole-genome sequencing data from 2,619 individuals through the UK10K program and deep-imputation data from 39,655 individuals genotyped genome-wide. Meta-analysis of the summary statistics from 19 cohorts identified in CYP2R1 the low-frequency (minor allele frequency = 2.5%) synonymous coding variant g.14900931G>A (p.Asp120Asp) (rs117913124[A]), which conferred a large effect on 25-hydroxyvitamin D (25OHD) levels (-0.43 SD of standardized natural log-transformed 25OHD per A allele; p value = 1.5 × 10-88). The effect on 25OHD was four times larger and independent of the effect of a previously described common variant near CYP2R1. By analyzing 8,711 individuals, we showed that heterozygote carriers of this low-frequency variant have an increased risk of vitamin D insufficiency (odds ratio [OR] = 2.2, 95% confidence interval [CI] = 1.78-2.78, p = 1.26 × 10-12). Individuals carrying one copy of this variant also had increased odds of multiple sclerosis (OR = 1.4, 95% CI = 1.19-1.64, p = 2.63 × 10-5) in a sample of 5,927 case and 5,599 control subjects. In conclusion, we describe a low-frequency CYP2R1 coding variant that exerts the largest effect upon 25OHD levels identified to date in the general European population and implicates vitamin D in the etiology of multiple sclerosis.

Keywords: GWAS; low-frequency genetic variants; multiple sclerosis; vitamin D.

Publication types

  • Meta-Analysis

MeSH terms

  • Cholestanetriol 26-Monooxygenase / genetics*
  • Cytochrome P450 Family 2 / genetics*
  • Gene Frequency
  • Genetic Predisposition to Disease / genetics*
  • Genome, Human / genetics
  • Genome-Wide Association Study
  • Humans
  • Multiple Sclerosis / etiology
  • Multiple Sclerosis / genetics*
  • Polymorphism, Single Nucleotide
  • Risk Factors
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood
  • Vitamin D Deficiency / diagnosis*
  • Vitamin D Deficiency / genetics*

Substances

  • Vitamin D
  • 25-hydroxyvitamin D
  • Cytochrome P450 Family 2
  • CYP2R1 protein, human
  • Cholestanetriol 26-Monooxygenase