Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease. “Autoimmune” means your immune system, which normally protects you, mistakenly attacks ...

Neurofibromatosis is a group of genetic conditions. In these conditions, small mistakes in certain genes make cells in nerves grow in the wrong way. This can ...

Neuroferritinopathy is a rare brain disorder where iron slowly builds up inside movement-control areas of the brain, especially the basal ganglia. The iron ...

Neuroblastoma is a cancer that starts in very young nerve cells. These young nerve cells are called “neuroblasts.” They are baby cells of the sympathetic ...

Neurodegeneration in diabetic retinopathy means the nerve cells in the retina start getting sick and dying because of diabetes—even before the classic “leaky ...

In normal life, tiny brain arteries feed the deep brain. If those vessels get sick or narrow, blood flow is not steady. Little clots may form. The brain wiring ...

CADASIL is a genetic small-vessel disease of the brain. It is caused by a harmful change (a “pathogenic variant”) in a gene called NOTCH3. This gene sits on ...

Bilingual aphasia is a language problem that happens after brain injury in a person who uses two languages.Aphasia means trouble using or understanding ...

Cerebral amyloid angiopathy is a brain blood-vessel problem. In CAA, tiny proteins called amyloid-beta (Aβ) build up in the walls of small and medium arteries ...

A ganglioglioma is a rare brain or spinal cord tumor. It has two parts in the same lump. One part is made of nerve cells (ganglion cells). The other part is ...

Choroid plexus papilloma (CPP) is a rare, usually benign (non-cancer) brain tumor that starts in the choroid plexus, the spongy tissue inside the brain’s fluid ...

Pilomyxoid astrocytoma is a rare brain tumor that starts from star-shaped support cells in the brain called astrocytes. Doctors first recognized it as a tumor ...

Obesity hypoventilation syndrome (OHS) is a breathing disorder that happens in people with obesity who do not breathe out enough carbon dioxide (CO₂) while ...

Ragged red fibers are not a single disease by themselves, but a very important clue that doctors sometimes see when they look at a tiny piece of muscle under a ...

Myoclonic epilepsy is a condition where the brain sends sudden, extra “spark” signals that make a muscle, or a group of muscles, jerk for a brief moment. The ...

Lymphocytic hypophysitis is inflammation of the pituitary gland caused by the body’s own immune system. The pituitary is a tiny “master gland” at the base of ...

Hypertrophic pachymeningitis (HP) means the dura mater—the tough outer covering of the brain and spinal cord—gets abnormally thick and inflamed. Hypertrophic ...

Anti-GAD antibody syndrome is an umbrella term for autoimmune conditions in which your immune system makes antibodies against an enzyme called glutamic acid ...

Neuro-ophthalmologic manifestations of ALS are the eye and vision problems that come from changes in the brain and nerves that control eye movement, eyelids, ...

Latent Autoimmune Diabetes of Adults, or LADA, is a type of diabetes that starts in adulthood and is driven by the immune system. In LADA, the immune system ...