Cerebellar degeneration is a process in which neurons (nerve cells) in the cerebellum—the area of the brain that controls coordination and balance—deteriorate and die. Diseases that cause cerebellar degeneration also can involve the spinal cord and other areas of the brain, including the medulla oblongata (which is involved in cardiac and respiratory systems), cerebral cortex (involved with thought consciousness, language, emotion, and other processes), and the brain stem.

Cerebellar degeneration may be the result of inherited genetic mutations that alter the normal production of specific proteins that are necessary for the survival of neurons. The disease also can be acquired (non-genetic). Symptoms may include:

• A wide-based, unsteady, lurching walk, often accompanied by a tremor in the trunk of the body
• Slow, unsteady and jerky movement of the arms or legs
• Slowed and slurred speech
• Rapid, small movements of the eyes (called nystagmus)

Diseases that are specific to the brain, as well as diseases that occur in other parts of the body, can cause neurons to die in the cerebellum. Neurological diseases that feature cerebellar degeneration include:

• Stroke, caused by a blood vessel that is either blocked or bleeding
• Cerebellar cortical atrophy, multisystem atrophy, and olivopontocerebellar degeneration – progressive disorders in which cerebellar degeneration is a key feature
• Friedreich ataxia and other spinocerebellar ataxias, which are caused by inherited genetic mutations that result in ongoing loss of neurons in the cerebellum, brain stem, and spinal cord
• Transmissible spongiform encephalopathies (such as Creutzfeldt-Jakob disease), in which abnormal proteins cause inflammation in the brain, including the cerebellum
• Multiple sclerosis, in which damage to the insulating membrane (myelin) that wraps around and protects nerve cells can involve the cerebellum

Acquired diseases that can cause cerebellar degeneration include:

• Chronic alcohol abuse that leads to temporary or permanent cerebellar damage
• Paraneoplastic disorders, in which cancer in a part of the body produces substances that cause immune system cells to attack neurons in the cerebellum.

There is no cure for hereditary forms of cerebellar degeneration. Treatment is usually supportive and is based on the person's symptoms or on disorders that may contribute to the cerebellar degeneration.

• Acute and hemorrhagic stroke can result in a lack of blood flow or oxygen to the brain, leading to the death of neurons in the cerebellum and other brain structures.
• Cerebellar cortical atrophy, multisystem atrophy and olivopontocerebellar degeneration are progressive degenerative disorders that affect various parts of the nervous system, including the cerebellum.
• Spinocerebellar ataxias, including Friedreich ataxia, are caused by inherited changes (mutations) in many different genes and are characterized by cell death in the cerebellum, brain stem, and spinal cord.
• Transmissible spongiform encephalopathies (such as 'Mad Cow Disease' and Creutzfeldt-Jakob disease) are associated with inflammation of the brain, particularly in the cerebellum, that is caused by abnormal proteins.
• Multiple sclerosis occurs when the insulating membrane (myelin) that wraps around and protects nerve cells (including those of the cerebellum) become damaged.