A study of tuberous sclerosis, a syndrome associated with autism, suggests a new treatment approach that could extend to other forms of autism.
The genetic disorder tuberous sclerosis complex (TSC) causes autism in about half of the children affected. Because its genetics are well defined, TSC offers a window into the cellular and network-level perturbations in the brain that lead to autism. A study published today by Cell Reports cracks the window open further, in an intriguing new way. It documents a defect in a basic housekeeping system cells use to recycle and renew their mitochondria.
Mitochondria are the organelles responsible for energy production and metabolism in cells. As they age or get damaged, cells digest them through a process known as autophagy (“self-eating”), clearing the way for healthy replacements. (Just this month, research on autophagy earned the Nobel Prize in Physiology or Medicine.)
Mustafa Sahin, MD, PhD, Darius Ebrahimi-Fakhari, MD, PhD, and Afshin Saffari, in Boston Children’s Hospital’s F.M. Kirby Neurobiology Center now report that autophagy goes awry in brain cells affected by TSC. But they also found that two existing medications restored autophagy: the epilepsy drug carbamazepine and drugs known as mTOR inhibitors. The findings may hold relevance not just for TSC but possibly for other forms of autism and some other neurologic disorders. …
One of the hardest parts of developing new treatments for autism spectrum disorder (ASD) is that almost every patient has a different combination of environmental and genetic risk factors. This suggests that every patient could take a unique path to their diagnosis. It is hard to come up with a single treatment that will help patients with fundamentally different root causes of ASD.
One way to approach this problem is to look for ways to cluster sub-types of autism for clinical trials, based on genetic risk factors or the types of neural circuits that are affected. If circuit dysfunction could be monitored and diagnosed easily in patients, it might be possible to develop treatments to reverse the dysfunction that cut across genetic and environmental causes of ASD. That is the hope of research on well-defined “syndromic” causes of autism such as tuberous sclerosis complex, Fragile X syndrome and Rett syndrome.
Accelerating research collaborations to design clinical trials for children with brain disorders, including ASD, is a major mission of Boston Children’s Hospital’s Translational Neuroscience Center (TNC).A recent study in Translational Psychiatry, led by Mathew Alexander, PhD, in the Boston Children’s lab of Lou Kunkel, PhD, in collaboration with the TNC and Pfizer, is a prime example. It suggests that patients with Duchenne muscular dystrophy (DMD) may constitute another subset of ASD patients — one that could benefit from phosphodiesterase (PDE) inhibitors, a family of drugs including Viagra. …