[P3-60] Association of Vitamin D-related Gene Polymorphisms with Serum 25(OH)D and Vitamin D Status in Malaysian Children with Epilepsy
Vitamin D deficiency is common in children with epilepsy (CWE) on long-term antiepileptic drugs (AEDs) treatment. Single nucleotide polymorphisms (SNPs), in the vitamin D pathway have been reported by previous studies to be as important as other potential risk factors for the serum 25-hydroxyvitamin D (25(OH)D) concentration. This cross-sectional study investigated vitamin D-related SNPs in relation to serum 25(OH)D concentrations in 239 ambulant CWEs on AEDs. Twelve SNPs in 7 genes (VDR, GC, CYP2R1, CYP24A1, CYP27B1, CYP27A1, CYP3A4) were genotyped using TaqMan assays, and serum 25(OH)D was measured using electrochemiluminescence immunoassay. Data regarding basic biochemical analyses, history of clinical epilepsy, anthropometry, physical activity and dietary intake history were also recorded. Linear regression and logistic regression models were used to assess associations between each SNP with serum 25(OH)D concentrations and presence of vitamin D deficiency, respectively, adjusted for covariates. Models were run separately by ethnicity, followed by fixed-effects meta-analysis to combine the results. Participants included 52.7% Malay, 24.3% Chinese and 23.0% Indian. Mean serum 25(OH)D was 58.8 nmol/L (SD 25.7); the prevalence of vitamin D deficiency (≤37.5nmol/L) was 22.9%. In the meta-analysis, minor allele of GC-rs4588 was significantly associated with lower serum levels of 25(OH)D (β=-8.11, P<0.004). In addition, VDR-rs7975232 was significantly associated with reduced odds of vitamin D deficiency in Malay cohort (Odds Ratio, 0.14; 95% Confidence Interval, 0.04-0.42; P<0.004). Our findings are the first to suggest that GC-rs4588 and VDR-rs7975232 may be genetic determinants of serum 25(OH)D concentration and vitamin D deficiency, respectively, in Malaysian CWE.