Genetic Cause of Fetal Alcohol-Related Developmental Disorders Found

A new animal study found a specific genetic cause of fetal alcohol-related developmental disorders. When pregnant women consume alcohol, the genetic processes that control thyroid hormone levels in the fetal brain are interfered with. Fetal alcohol exposure can cause neurodevelopmental disorders such as emotional behavioral disorders and deficits in learning, memory, and speech. Past animal research has shown 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. There is currently no treatment for this. Laura Sittig, author of the study and a student at Northwestern University Feinberg School of Medicine, says that specific concentrations of thyroid hormone levels in the brain are necessary to support normal neurological development. Sittig and her colleagues hypothesized that alcohol exposure in the womb leads to cognitive impairment by inducing changes to DNA that do not alter the actual DNA sequences of developmental genes like Dio3, one of the enzymes that controls thyroid hormone levels in the fetal brain. They used rats to model moderate alcohol consumption during pregnancy. Their findings demonstrated that alcohol exposure disrupts the “imprinting” of Dio3, which normally originates from the father’s gene. Alcohol disrupts the paternal-maternal dosage of Dio3, which increases the amount of the enzyme present in specific brain regions of the fetus. This increase reduces vital thyroid hormones in areas of the brain that control learning, memory, and emotional behaviors. “In light of our current finding, we can begin testing specific dietary supplements that could reverse the epigenetic alterations that disrupt the regulation of Dio3,” Sittig said. “When given to the mother or newborn, this might correct the imprinting deficits induced by alcohol…This is a promising avenue to improve the prognosis of alcohol-related neurodevelopmental disorders, for which we currently have no intervention strategy.” Source: Science Daily, June 2009

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