A new JACI paper claims
in three independent birth cohorts (N=60, N=30, N=28) DNA methylation at the SMAD3 promoter was selectively increased in asthmatic children of asthmatic mothers and was associated with risk of childhood asthma.
although associations between SMAD3 variants rs17228058, rs744910, rs17294280 and asthma have been reported in GWAS, asthma-related SMAD3 methylation differences were unlikely to be influenced by SMAD3 genotype
while I am not convinced as it is common wisdom that
If a SNP interferes with or alters a TF binding site, it could potentially affect both DNA methylation and gene expression independently.
So this possibility needs to be excluded before drawing any conclusions. BTW, SMAD3 is a well know vitamin D target…
1,25-dihydroxyvitamin D3–bound [1,25(OH)2D3-bound] vitamin D receptor (VDR) specifically inhibits TGF-β–SMAD signal transduction through direct interaction with SMAD3.
while so far only IL2 methylation was linked to asthma (another super Vitamin D target).
I believe this already since my first step into the vitamin D field but only now a review shows that
The integration of all these genome-wide data facilitates the identification of the most important VDR binding sites and associated primary 1,25(OH)2D3 target genes. Expression changes of these key genes can serve as biomarkers for the actions of vitamin D3 and its metabolites in different tissues and cell types of human individuals. Analysis of primary tissues obtained from vitamin D3 intervention studies using such markers indicated a large inter-individual variation for the efficiency of vitamin D3 supplementation.
It is a continuous medical malpractice to supplement newborn children with vitamin D without taking into account variation of the inter-individual response, body weight, or any co-medication.
I had already a thread here about asthma and iatrogenic factors last month including estrogens, vaccines, antibiotics, vitamin D, paracetamol, and Caesarean section. There may be even another kid on the block: folate. At least in mice in utero supplementation with methyl donors enhances allergic airway disease Continue reading Asthma: a iatrogenic disease cont’d