Genetic disease offers insights for Parkinson’s treatment

A new study suggests that a rare nerve disorder called giant axonal neuropathy (GAN) may offer insights into Parkinson’s disease. Researchers at Northwestern University and the University of North Carolina found that GAN causes a buildup of certain proteins, which prevents nerve cells from clearing waste properly. Since similar issues occur in Parkinson’s, this research may help scientists find new ways to slow or treat the disease. What Is Giant Axonal Neuropathy (GAN)? GAN is a rare genetic condition that starts in childhood and affects the nervous system. It happens when a faulty gene prevents the body from making a protein called gigaxonin, which helps break down and clear out nerve cell waste. Without gigaxonin, certain proteins (called neurofilaments) build up inside nerve cells and cause damage. Neurofilaments help nerve cells keep their shape and send signals. When nerve cells are injured, neurofilaments leak into the fluid around the brain and spine and eventually into the bloodstream. Because of this, they can be measured and used as a sign (biomarker) of nerve damage. How Does This Relate to Parkinson’s Disease? Researchers have found that high levels of a specific neurofilament, called neurofilament light chain, are linked to early Parkinson’s symptoms like sleep problems. Higher levels may also predict how quickly Parkinson’s symptoms progress. Since neurofilament buildup is seen in several brain disorders—including Parkinson’s, Alzheimer’s, and multiple sclerosis—scientists are studying whether it could help track disease progression and develop new treatments. How Do Neurofilaments Affect the Brain? To better understand the role of neurofilaments in brain diseases, scientists used a mouse model of GAN. Studying GAN is helpful because, unlike other brain disorders, it is directly caused by neurofilament buildup, making it easier to see their effects. The study showed that when neurofilaments build up, they block the nerve cell’s waste removal system. This happens in two ways: Blocked waste transport: Normally, waste is carried to the cell’s “garbage disposal” (lysosomes) for recycling. But in GAN, the waste-carrying vesicles get stuck and can’t do their job. Disrupted cleanup signals: Neurofilaments also interfere with proteins that help regulate waste removal, making the problem worse. What Does This Mean for Parkinson’s? Parkinson’s disease also involves problems with waste removal in nerve cells. In Parkinson’s, faulty waste clearance allows toxic proteins (like alpha-synuclein) to build up, leading to the loss of dopamine-producing cells. Since dopamine is needed for movement and coordination, this cell loss leads to the movement symptoms of Parkinson’s. This study suggests that improving waste removal in nerve cells could be an important approach to slowing or treating Parkinson’s. Future research will focus on understanding how neurofilament buildup affects brain health and whether targeting this process could help people with Parkinson’s and other neurological conditions.