Down's syndrome 'linked to brain protein loss'

Researchers looked at how proteins powered brain
function and memory

A lack of a protein in Down's syndrome brains could be the cause of learning and memory problems, says a US study.

Writing in Nature Medicine, Californian researchers found that the extra copy of chromosome 21 in people with the condition triggered the protein loss.

Their study found restoring the protein in Down's syndrome mice improved cognitive function and behaviour.

The Down's Syndrome Association said the study was interesting but the causes of Down's were very complex.

Prof Huaxi Xu, senior author of the study from the Sanford-Burnham Medical Research Institute, said that in experiments on mice they discovered that the SNX27 protein was important for brain function and memory formation.

Mice with less SNX27 had fewer active glutamate receptors and therefore had impaired learning and memory.

The SNX27-deficient mice shared some characteristics with Down's syndrome, so the researchers looked at human brains with the condition.

This confirmed their findings in the lab - that people with Down's syndrome also have significantly lower levels of SNX27.


Neurons from a normal mouse (left) are longer and fuller than neurons from a mouse lacking SNX27 (right)
"So, in Down's syndrome, we believe lack of SNX27 is at least partly to blame for developmental and cognitive defects," Prof Xu said.

- BBC.co.uk