Pelizaeus-Merzbacher Disease (PMD) is a rare, genetic condition affecting around 1 in 200,000 to 500,000 males in the United States. PMD damages the nervous system, leading to serious problems with movement, coordination, and thinking. In its most severe form, children with PMD often do not live past the age of 10. Sadly, there is currently no treatment.

Neurons in the brain talk to each other through connecting cables that are often wrapped in a fatty sheath called myelin. The myelin helps the signals travel between neurons. Patients with PMD have too little myelin, and without the myelin coating, signals in the brain and body can’t travel properly.

One known cause of this dangerously low level of myelin in PMD patients is a genetic mutation that alters PLP1, the gene for a protein involved in making myelin. Thanks to support from the National Institutes of Health, in 2020, Dr. Paul Tesar and his lab at the Case Western Reserve School of Medicine developed a promising new treatment. They are using a new class of drugs called antisense oligonucleotides—tiny strands of genetic material that can turn off harmful genes. They tried targeting these to PLP1, hoping that reducing the amount of defective Plp1 protein would help myelin get closer to its normal levels and function. In lab tests, this treatment led to remarkable results, helping mice with PMD live much longer—from just 3 weeks to 8 months.

Now, this drug is being tested in Phase 2 clinical trials, where researchers are studying how well it works and how safe it is for people. While results are still out, it is clearly a very important approach to pursue–made possible by federal funding and offering some hope in the fight against an otherwise devastating disease.