Defective Immune Cells Cause Rare Childhood Neurological Disorders

A recent University of Sheffield news release explores findings which highlight a potential cause of leukodystrophies: immune cells. This group of rare childhood neurological disorders impacts the myelin sheath, the protective coating around the brain’s nerve cells. In understanding how and why these disorders occur, researchers may better create targeted therapies moving forward. You can find the full research findings in Glia.

Leukodystrophies: Childhood Neurological Disorders

The National Organization for Rare Disorders (NORD) classifies leukodystrophies as:

rare, progressive, metabolic, genetic diseases that affect the brain, spinal cord and often the peripheral nerves.

Gene abnormalities destroy the brain’s white matter. Because of this, these disorders may also be called hereditary white matter disorders. Symptoms vary based on the disorder. However, they can include problems with movement and balance, loss of memory, and changes in behavior. These often occur within one year of birth and grow progressively worse.

Subsets of these childhood neurological disorders include Canavan disease, Alexander disease, Krabbe disease, GM1 gangliosidosis, Refsum disease, and X-linked adrenoleukodystrophy, among others. Few treatments exist.

The Findings

According to researchers, leukodystrophies often develop during pregnancy. During fetal brain development, some neurons die. Microglia, cells which mediate immune response, digest dead and damaged cells. However, defective microglia may lead to an immune response in which myelin and nerve cells are mistakenly attacked.

Researchers tested their hypothesis on zebrafish models. As many animals do not have the same brain capacity or abilities as humans, researchers specifically developed these zebrafish models of human leukodystrophy for testing.

In these models, microglial issues were observed during neuronal development. Broken, deficient, or damaged microglia with defective lysosomes could not digest neurons. As a result, the immune system stimulated neuronal inflammation to fight these perceived invaders.

Next, additional human-oriented research is needed to see if results can be replicated.