Autism is clearly hereditary, but researchers have struggled to find the link between the condition and specific genes. Now, a team has devised a process for connecting a suspect gene to its function in autism. This should make diagnosis and strategic treatment plans much easier as well as inspire new drug treatments.
An inheritable neurological disorder, but with what gene?
Mutations in one autism-linked gene, called NHE9 which is involved in transporting substances in and out of structures within the cell, causes communication problems among brain cells that likely contribute to autism. “Autism is considered one of the most inheritable neurological disorders, but it is also the most complex,” said Rajini Rao, PhD, professor of physiology in the Institute for Basic Biomedical Sciences at the Johns Hopkins University School of Medicine. “There are hundreds of candidate genes to sort through, and a single genetic variant may have different effects even within the same family. This makes it difficult to separate the chaff from the grain, to distinguish harmless variations from disease-causing mutations. We were able to use a new process to screen variants in one candidate gene that has been linked to autism, and figure out how they might contribute to the disorder.”
The NHE9 gene is the likely candidate
The NHE9 gene has long been suspect in such disorders attention deficit disorder, addiction and epilepsy as well as autism spectrum disorders. Rao’s test ran in three steps. First, they used a model to predict how autism-linked variants in the NHE9 gene would affect the protein’s shape and function. Some cause dramatic damage, some more subtle. Next, they tested how the variant forms of NHE9 would impact a simple organism. They chose yeast. For the mutations which had a detectable effect on the yeast, they next tested on mice. Using lab grown mouse cells with variant forms of NHE9 researchers found a change in the pH (acidity) inside cellular compartments which altered the cells’ ability to function properly.
New drugs, treatment and better identification of at-risk patients
Now that the team has pinpointed the importance of this mechanism in autism, this could lead to the development of new drugs which would alter the cellular pH. The development of the screening test could also help identify gene variants and at-risk patients.
Source: MedicalNewsToday, Nature Communications