09-08-2006, 02:09 PM
A previously unrecognised trigger for autism may have been found, in the form of mutations that affects neuron development in a brain region important for learning and social interaction.
Autism is around four times more common in boys than girls, which suggests that mutations on the X chromosome play a role, as boys lack a second X chromosome that could compensate for any genetic abnormality. Studies have identified several hundred gene candidates, but no conclusive links to a specific mutation.
Now a 15-year-long international screening effort has identified two different mutations of the same X chromosome gene, which seem to be linked to autism in two unrelated families (Molecular Psychiatry, DOI: 10.1038/sj.mp.4001883). The gene encodes a protein called L10, a vital component of ribosomes - the structures that build proteins. L10 is most actively manufactured in the hippocampus, a brain region important in learning and memory as well as some social and emotional functions.
Lead author Sabine Klauck of the Division of Molecular Genome Analysis at the German Cancer Research Centre in Heidelberg says the mutations are rare, and not present in their other patients. But they do reveal an important pathway by which different genetic defects could lead to different types of autism.
Essi Viding of University College London says the findings are in line with structural brain changes seen in autism, but cautions that many other genes will be involved.
From issue 2568 of New Scientist magazine, 08 September 2006, page 20
Autism is around four times more common in boys than girls, which suggests that mutations on the X chromosome play a role, as boys lack a second X chromosome that could compensate for any genetic abnormality. Studies have identified several hundred gene candidates, but no conclusive links to a specific mutation.
Now a 15-year-long international screening effort has identified two different mutations of the same X chromosome gene, which seem to be linked to autism in two unrelated families (Molecular Psychiatry, DOI: 10.1038/sj.mp.4001883). The gene encodes a protein called L10, a vital component of ribosomes - the structures that build proteins. L10 is most actively manufactured in the hippocampus, a brain region important in learning and memory as well as some social and emotional functions.
Lead author Sabine Klauck of the Division of Molecular Genome Analysis at the German Cancer Research Centre in Heidelberg says the mutations are rare, and not present in their other patients. But they do reveal an important pathway by which different genetic defects could lead to different types of autism.
Essi Viding of University College London says the findings are in line with structural brain changes seen in autism, but cautions that many other genes will be involved.
From issue 2568 of New Scientist magazine, 08 September 2006, page 20