Low levels of SNX27 causes symptoms of Down syndrome; condition is treatable in mice

Reading about this today has improved my mood, seems like exciting stuff. Published online yesterday.


Researchers discover that the extra chromosome inherited in Down syndrome impairs learning and memory because it leads to low levels of SNX27 protein in the brain.

The study, published March 24 in Nature Medicine (link here), shows that SNX27 is reduced in human Down syndrome brains. The extra copy of chromosome 21 means a person with Down syndrome produces less SNX27 protein, which in turn disrupts brain function. What’s more, the researchers showed that restoring SNX27 in Down syndrome mice improves cognitive function and behavior.

“In the brain, SNX27 keeps certain receptors on the cell surface—receptors that are necessary for neurons to fire properly,” said Huaxi Xu, Ph.D., Sanford-Burnham professor and senior author of the study.

“So, in Down syndrome, we believe lack of SNX27 is at least partly to blame for developmental and cognitive defects.”

A more sciency explanation from further down in the article:

They found that SNX27 helps keep glutamate receptors on the cell surface in neurons. Neurons need glutamate receptors in order to function correctly. With less SNX27, these mice had fewer active glutamate receptors and thus impaired learning and memory.

Some hope:

“Everything goes back to normal after SNX27 treatment. It’s amazing—first we see the glutamate receptors come back, then memory deficit is repaired in our Down syndrome mice,” said Xin Wang, a graduate student in Xu’s lab and first author of the study.

“Gene therapy of this sort hasn’t really panned out in humans, however. So we’re now screening small molecules to look for some that might increase SNX27 production or function in the brain.”

The rest of the article I was reading is here, but I recommend reading the Nature article if you have a science background because it has extra pics explaining the research.

Here’s a link to where you (Canadians) can donate, I have no connection to the charity:

Canadian Down Syndrome Society