Gene linked to low IQ

Gene linked to low IQ

(Medical Xpress)—Children with both a common gene variant and lower thyroid hormone levels, which occurs in approximately 4% of the population, are four times more likely to have a low IQ, according to research presented today by the University at the Society for Endocrinology annual BES conference.

It is well established that thyroid hormones are essential for brain development in childhood. More recently, scientists have looked at a certain enzyme, called deiodonase-2, involved in processing thyroid hormones inside cells. A variant in the gene coding this enzyme has already been associated with key health outcomes including diabetes and high blood pressure, although the precise mechanism remains unclear.

In this study, researchers from Cardiff and the University of Bristol examined the genetic data and thyroid function of 3,123 aged 7 who also had their IQ tested, as part of the Avon Longitudinal Study of Parents and Children (ALSPAC). The researchers found that children with thyroid hormone levels in the lower part of the normal population range who also possessed this genetic variant were four times more likely to have an IQ under 85.

This result stood true after taking into account various differences in environmental and socio-economic factors such as social class. Children with lower thyroid hormone levels alone did not have an increased risk of lower IQ, highlighting that without genetic analysis the population at risk could not be identified.

The study's results will need to be confirmed in other groups of children. "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," said lead researcher Dr Peter Taylor, from the School of Medicine. "Children with satisfactory thyroid 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 processing," he added.

add to favorites email to friend print save as pdf

Related Stories

Thyroid problems linked to irregular heart rhythm

Nov 28, 2012

People with an overactive thyroid gland (hyperthyroidism) carry a greater risk of developing irregular heart rhythm (known as atrial fibrillation) than those with normal thyroid function, finds a study published on BMJ today. ...

Recommended for you

A nucleotide change could initiate fragile X syndrome

22 hours ago

Researchers reveal how the alteration of a single nucleotide—the basic building block of DNA—could initiate fragile X syndrome, the most common inherited form of intellectual disability. The study appears ...

Gene clues to glaucoma risk

Aug 31, 2014

Scientists on Sunday said they had identified six genetic variants linked to glaucoma, a discovery that should help earlier diagnosis and better treatment for this often-debilitating eye disease.

Mutation disables innate immune system

Aug 29, 2014

A Ludwig Maximilian University of Munich team has shown that defects in the JAGN1 gene inhibit the function of a specific type of white blood cells, and account for a rare congenital immune deficiency that ...

Study identifies genetic change in autism-related gene

Aug 28, 2014

A new study from Bradley Hospital has identified a genetic change in a recently identified autism-associated gene, which may provide further insight into the causes of autism. The study, now published online in the Journal of ...

NIH issues finalized policy on genomic data sharing

Aug 27, 2014

The National Institutes of Health has issued a final NIH Genomic Data Sharing (GDS) policy to promote data sharing as a way to speed the translation of data into knowledge, products and procedures that improve health while ...

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

katesisco
not rated yet Mar 25, 2014
The common unstated thyroid condition may be responsible for the 50% of women who are said not to have underarm perspiration, the 50% of women said not to be orgasmic, the 50% of LD children who mature with the dysfunction still present, ad nauseum. Perhaps the complex interactions of the HPA axis is at the base of this malfunction.