The gene behind the supplement marketing is real
Across 19 case-control studies of 2228 affected babies and 4220 controls, the fetal C677T version of MTHFR, the enzyme that activates folate, was commoner in affected babies.
What the study found
The MTHFR C677T variant does track with neural tube defect risk
The gene behind the supplement marketing is real. Across 19 case-control studies, 2228 affected babies and 4220 controls, the fetal C677T version of MTHFR, the enzyme that activates folate, was commoner in babies with a neural tube defect, and with spina bifida specifically.
The caveat · No figure for how big the risk is
A risk factor is not a diagnosis, and nothing here shows that carriers need a different supplement or a different dose. Pooled case-control genetic studies are prone to small-study effects and to population mismatch between cases and controls, so a significant pooled result is much weaker than the same result from trials. No odds ratio is reported, so the size of the association cannot be stated. The association did not hold in mixed populations, and nobody has explained why.