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ABSTRACT: Background
Multiple sclerosis (MS) risk is determined by both genes and environment. One of the most striking features of MS is its geographic distribution, particularly the pattern of high MS frequency in areas with low sunlight exposure, the main inducer of vitamin D synthesis. Recent epidemiologic, experimental, and clinical evidence support an effect for low environmental supplies of vitamin D in mediating an increased susceptibility to MS.Objectives
We 1) examined the association of serum 25-hydroxy-vitaminD [25(OH)D] concentrations and MS status and 2) assessed the genetic contribution to serum 25(OH)D concentrations and tested for its association with genetic variants in 2 candidate genes [vitamin D receptor and 1-alpha-hydroxylase (CYP27B1)].Design
We used a twin study approach, comprising adult pairs identified from the longitudinal population-based Canadian Collaborative Project on Genetic Susceptibility to MS. Monozygotic (MZ; n = 40) and dizygotic (DZ; n = 59) pairs, both concordant and discordant for MS, were studied. End-of-winter serum 25(OH)D concentrations were measured by radioimmunoassay, and genotypes were assessed by single nucleotide polymorphism (SNP) assay.Results
Serum concentrations of 25(OH)D were highly correlated in MS-concordant pairs (r = 0.83, P < 0.001), but they were not significantly associated with having the disease (P = 0.4) when analyzed by logistic regression. Intraclass correlation for 25(OH)D concentration was significantly greater in MZ pairs (MZ, r: 0.71 > DZ r: 0.32, P = 0.006). Significant associations of 2 CYP27B1 SNP variants and 25(OH)D concentrations were observed.Conclusion
The findings indicate important genetic influences on regulation of seasonal circulating 25(OH)D concentrations in MS twins.
SUBMITTER: Orton SM
PROVIDER: S-EPMC2740974 | biostudies-literature | 2008 Aug
REPOSITORIES: biostudies-literature
Orton Sarah-Michelle SM Morris Andrew P AP Herrera Blanca M BM Ramagopalan Sreeram V SV Lincoln Matthew R MR Chao Michael J MJ Vieth Reinhold R Sadovnick A Dessa AD Ebers George C GC
The American journal of clinical nutrition 20080801 2
<h4>Background</h4>Multiple sclerosis (MS) risk is determined by both genes and environment. One of the most striking features of MS is its geographic distribution, particularly the pattern of high MS frequency in areas with low sunlight exposure, the main inducer of vitamin D synthesis. Recent epidemiologic, experimental, and clinical evidence support an effect for low environmental supplies of vitamin D in mediating an increased susceptibility to MS.<h4>Objectives</h4>We 1) examined the associ ...[more]