In a surprising new finding, a Northwestern Medicine® study has found a common molecular vulnerability in autism and fetal alcohol spectrum disorder. Both disorders have symptoms of social impairment and originate during brain development in utero.
This is the first research to explore a common mechanism for these disorders and link their molecular vulnerabilities.
The study found male offspring of rat mothers who were given alcohol during pregnancy have social impairment and altered levels of autism-related genes found in humans. Female offspring were not affected.
But the alcohol damage can be reversed. A low dose of the thyroid hormone thyroxin given to alcohol-consuming rat mothers at critical times during their pregnancy alleviated social impairments and reversed the expression of autism-related genes in their male offspring, the study reports.
“The beneficial effects of thyroxin in this animal model raises an exciting question – whether novel drug targets and treatments could be developed for both these disorders,” said Eva Redei, psychiatry and behavioral sciences and the senior author of the study.
The study was published June 13, 2013, in the journal Alcoholism: Clinical & Experimental Research.
Redei stresses caution in interpreting these results for their relevance to treatments in human fetal alcohol spectrum disorder and autism spectrum disorder.
“Human studies are needed to establish that the parallel we saw in the animal model exists in these diseases,” Redei says. The study does not mean alcohol consumed by the mother is the cause of autism, she emphasizes.
“The novel finding here is that these two disorders share molecular vulnerabilities, and if we understand those, we are closer to finding treatments,” says Redei.
Redei decided to investigate a possible link between the two disorders when she observed similarities between the two. Both are neurodevelopmental, have symptoms of social impairment and affect males more or differently than females. Autism affects males versus females in a nine to one ratio; social impairment in this model of alcohol spectrum disorder is male specific.
In the current study, Redei wanted to find the smallest dose of thyroid hormone that effectively reverses the behavioral consequences of fetal alcohol spectrum disorder.
“We wanted to find the smallest dose to correct the behavioral abnormalities that wouldn’t create an overly high level of thyroid hormones during development, which can be detrimental,” Redei says.
Elif Tunc-Ozcan, the lead study author and a graduate student in Redei's lab, is researching how prenatal thyroid hormone supplementation reverses the behavioral deficits in the fetal alcohol spectrum disorder model.
"If our study proves to be relevant to human fetal alcohol spectrum disorder and, perhaps, even for autism spectrum disorder, it could help those suffering from these disorders," Tunc-Ozcan says.
By Marla Paul