A new genetic test can help identify risk of low IQ in babies shortly after their birth, scientists reveal.
For the analysis, scientists from the universities of Cardiff and Bristol UK, collected genetic data on 3,123 children aged seven. All the children were part of the Avon Longitudinal Study of Parents and Children. IQ levels of the children were measured and recorded at age eight.
Researchers found that presence of a gene combined with low levels of thyroid hormone (hypothyroidism) placed children at greater risk of low IQ than others. The gene, thus identified, produced an enzyme called deiodonase-2 that manages thyroid hormones within cells, Daily Mail reported.
Children having a low level of the thyroid hormone and the gene variant will be at four time higher risk of possessing an IQ under 85, researchers said.
"If other studies confirm our finding then there may be benefit in carrying out a genetic test for this gene variant in addition to the standard neonatal thyroid screening, which would identify children most at risk of developing low IQ," Dr Peter Taylor, from the Cardiff University, told Daily Mail. "Children with satisfactory thyroid hormone levels together with the genetic variant have normal IQ levels, which raises the possibility that children at risk could be treated with standard thyroid hormone tablets to compensate for impaired thyroid hormone processing."
Dr Taylor presented the study at the Society for Endocrinology BES 2014 meeting, held in Liverpool.
Similar to the current study, in 1999, a study published in the New England Journal of Medicine linked maternal hypothyroidism in pregnancy to low IQ in children.
Previous studies have also shown certain other factors that influence a child's intelligence levels. They include high blood pressure in pregnancy, use of an anti- epileptic drug valproate after conceiving, maternal iodine deficiency, IVF (in vitro fertilization) treatment for male infertility and exposure to fire retardants in pregnancy.