25 April 2017
New gene linked to autism
Published online 15 December 2016
Scientists zero in on harmful genetic mutations that trigger autism.
Certain types of branched-chain amino acids are essential for the normal functioning of the brain; a deficiency of these can lead to neurological abnormalities, including autism.
Now, researchers from Austria, Libya and Qatar have discovered how novel mutations in a gene called SLC7A5 leads to autism1. The mutations disrupt the activities of a specific transporter protein that carries certain types of branched-chain amino acids into the brain, consequently depleting amino acids in the brain, crippling nerve cells and eventually causing autism.
Such mutations were found in autistic patients born to consanguineous marriages, raising hopes for therapeutic interventions.
To understand how SLC7A5 mutations lead to autism, the scientists deleted the equivalent gene in mice. Levels of amino acids in mice brain were reduced, robbing them of their ability to socialize with other mice – a distinct symptom of autism.
However, directly injecting the missing amino acids into the rodents’ brains considerably improved their behaviour.
“This could potentially be used to treat certain symptoms presented in this form of autism in mice, refuting the idea that autism is irreversible,” says principal scientist Gaia Novarino from the Institute of Science and Technology, Austria.
- Tarlungeanu, D. C. et al. Impaired amino acid transport at the blood brain barrier is a cause of autism spectrum disorder. Cell http://dx.doi.org/10.1016/j.cell.2016.11.013 (2016).