Autism and Prenatal Vitamins
Irva Hertz-Picciotto, Ph.D., MPH
University of California, Davis
NIEHS Grants P01ES011269 and R01ES015359
In a population-based case control study of 566 subjects comparing a group of autistic children to a matched control group of children with normal development, researchers found that mother who didn't take prenatal vitamins were at greater risk of having an autistic child, and certain genetic markers markedly increased the risk.
Researchers examined maternal intake of prenatal vitamins in the 3 months before conception and the first month of pregnancy, and they looked for genotypes associated with autism. There was a dose/response relationship: the more prenatal vitamins a woman took, the less likely she would have an autistic child. There was no association with other types of multivitamins, and no association with prenatal vitamin intake during months 2-9 of pregnancy. Having certain genotypes also increased the odds that a woman would have an autistic child. Children with the COMT 472 AA gene were at increased risk of autism. If their mothers took prenatal vitamins, the odds ratio for the risk of autism was 1.8; if their mothers didn't, the odds ratio jumped to 7.2. This suggests that the maternal-fetal environment can magnify the effects of a susceptibility gene.
The authors think there are plausible biological explanations. Folate and other B vitamins are critical to neurodevelopment. The gene variants were in one-carbon metabolism pathways; therefore suggesting that methylation mechanisms may be responsible.
Citation: Citation: Schmidt RJ, Hansen RL, Hartiala J, Allayee H, Schmidt LC, Tancredi DJ, Tassone F, Hertz-Picciotto I. Prenatal vitamins, one-carbon metabolism gene variants, and risk for autism. Epidemiology. 2011 Jul 22(4):476-485.
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