Alcohol consumption by pregnant women hinders brain development in their children by interfering with the genetic processes that control thyroid hormone levels in the fetal brain, a new animal study found. Results will be presented Wednesday at The Endocrine Society's 91st Annual Meeting in Washington, D.C.
Fetal alcohol exposureeven from moderate drinking during pregnancycan cause neurodevelopmental disorders, such as emotional behavioral disorders and deficits in learning, memory and speech. There is currently no treatment for these problems, said the author who will present the study results, Laura Sittig, a student at Northwestern University Feinberg School of Medicine.
Past animal research shows that some of these lasting cognitive impairments occur because alcohol consumption during pregnancy decreases the level of maternal thyroid hormones and, therefore, fetal thyroid hormones.
"Specific concentrations of thyroid hormones must be available in the fetal brain to support normal neurological development," Sittig said.
One of the enzymes that control thyroid hormone levels in the fetal brain is the iodothyronine deiodinase type III, or Dio3, she explained.
Sittig and her colleagues hypothesized that alcohol exposure in the womb leads to cognitive impairments by inducing epigenetic alterationschanges to DNA that do not alter the actual DNA sequenceof developmental genes like Dio3 in the fetal brain. To investigate this hypothesis, they used rats to model moderate alcohol consumption during pregnancy.
The study, which was funded by the National Institutes of Health, demonstrated that fetal alcohol exposure disrupts the epigenetic "imprinting" of Dio3. In this process, Dio3 normally originates from the father's gene, while the maternal gene is silenced by epigenetic control. But alcohol exposure changes the paternal-maternal dosage of Dio3, which increases the amount of the enzyme present in specific brai
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The Endocrine Society