rs3755967

A bidirectional two-sample Mendelian randomization study examining the causal relationship between 25-hydroxyvitamin D levels and attention-deficit/hyperactivity disorder (ADHD). Using 79,366 European individuals for vitamin D GWAS data and 19,099 ADHD cases with 34,194 controls, the study found no evidence of a causal effect of vitamin D on ADHD (IVW β = -0.043, p = 0.833) or reverse causality. Although rs12785878 showed a nominal association with increased ADHD risk at higher vitamin D levels (p = 0.024), this did not survive multiple testing correction.

This case-control study of 288 Spanish RLS patients and 325 controls examined vitamin D metabolism genes and serum vitamin D levels. Serum 25-hydroxyvitamin D levels were significantly higher in RLS patients (21.94 ng/mL vs 18.63 ng/mL, p=0.0002), but seven SNPs in VDR and GC genes showed no association with RLS risk. However, RLS patients carrying the rs7975232CC genotype had higher frequency of response to GABAergic drugs.

This case-control association study of 815 Chinese pregnant women identified five SNPs in the GC (vitamin D-binding protein) gene significantly associated with serum 25-hydroxyvitamin D concentration: rs17467825, rs4588, rs2282679, rs2298850, and rs1155563. Mean 25(OH)D level was 15.67±7.98 ng/mL with 75% prevalence of deficiency. An XGBoost model incorporating these SNPs plus environmental factors achieved AUC 0.828 for predicting 25(OH)D deficiency risk. The study suggests maternal vitamin D deficiency may increase macrosomia risk (12 of 16 macrosomic infants had deficient mothers).