Karolinska Institutet study links TORCH infections to autism risk

A large-scale study from Karolinska Institutet, published in JAMA Pediatrics, has linked rare TORCH infections passed from a pregnant woman to a fetus with significantly increased risks of autism and intellectual disabilities.

Researchers analyzed health and education records for 3.7 million people born in Sweden between 1987 and 2011. The study found that children with congenital TORCH infections—which include pathogens such as cytomegalovirus, rubella, toxoplasmosis, and herpesvirus—were approximately three times more likely to be diagnosed with autism. Furthermore, these children were more than seven times more likely to have an intellectual disability, and up to 30 times more likely to experience severe to profound intellectual disability.

While researchers noted that these infections are unusual and account for a very small proportion of total autism cases in the general population, the risk for affected individuals is clearly elevated. The pathogens involved can sometimes cross the placenta to cause congenital infections in the developing fetus.