We’re Already on the Way to Gene Therapy for Rett Syndrome

Rett syndrome is a severe, genetic neurological disorder, which primarily affects girls. While it was once thought to be a form of autism, it’s now understood as its own condition. It affects breathing, as well as movement and coordination. Many patients are not able to speak, and some experience seizures. Frequently, Rett syndrome patients have a shortened lifespan. To learn more about Rett syndrome, click here.

If you, or someone you love, has a genetic condition, you’ve probably heard the recent buzz around gene therapy. Over the past few years, scientists have been working on using viruses to enter living cells with a faulty gene, remove the specific portion of the gene with the error, and replace it with a corrected version. This is a ground-breaking development in modern medicine, because this technique allows you to correct mutations in living cells.

Nine out of ten people with Rett syndrome have the same mutation– an error in the MECP2 gene– which makes the condition a prime candidate for gene therapy. Researchers have already begun looking into how to use gene therapy to help patients with Rett syndrome, and have made great progress.

Back in 2007, scientists started looking into gene therapy for Rett syndrome. They started with adult and juvenile mice, and discovered they could use a virus with the fixed MECP2 to actually reverse various Rett symptoms.

When the researchers injected more of the virus, greater levels of MECP2 were produced– which leads to the catch, called the “Goldilocks zone.” Just like Goldilocks couldn’t settle for a bowl of porridge that was a little too hot, or a little too cold, gene therapy also cannot deviate from the perfect, precise dose. While people with Rett syndrome have too little MECP2, delivering a smidgen too much MECP2 can also have harmful effects, such as MECP2 duplication syndrome. Interestingly, MECP2 duplication syndrome causes many of the same symptoms as Rett syndrome. Researchers need to find a dose that’s just right before the technique can treat humans.

The researchers found a dose that worked well on mice– all of the mice modeling Rett syndrome who received treatment fared better and lived longer than those without. Right now, scientists at Ohio State University in Columbus are taking the research one step closer to human patients: monkey patients.

The team studied cynomolgus monkeys, also known as crab-eating macaques. They administered the virus by injecting it into the spinal fluid of two 1-year-old monkeys, who served as controls. They found that this treatment double MECP2 throughout the monkeys’ bodies. After monitoring the first two monkeys, they treated three more with the virus. They then observed them for 18 months.

The treatment didn’t interfere with body weight, behavior, liver enzymes, or blood parameters– which implies there are not serious side effects, and this promising avenue of research is set to move forward.

Read more about this research on Spectrum News here.



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