Genetics

This post covers a 2021 Biochemical Genetics review by Scazzone and colleagues on SNPs in 12 vitamin D pathway genes and multiple sclerosis susceptibility. It walks the pathway from skin synthesis through hepatic and renal hydroxylation, transport by VDBP, and receptor action; then examines why VDR, CYP27B1, CYP24A1, and GC have produced two decades of contradictory results despite functional and GWAS support. It flags FGF-23, Klotho, MARRS, and the megalin-DAB2-cubilin system as effectively untested, and argues the field's null result reflects underpowered candidate-gene design plus unstandardised 25(OH)D measurement rather than absent biology.