Neurodegenerative disease

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Neurodegenerative disease

Neurodegenerative disease (Greek νέυρο-, néuro-, "nerval" and Latin dēgenerāre, "to decline" or "to worsen") is a condition in which cells of the brain and spinal cord are lost. The brain and spinal cord are composed of neurons that do different functions such as controlling movements, processing sensory information, and making decisions. Cells of the brain and spinal cord are not readily regenerated en masse, so excessive damage can be devastating. Neurodegenerative diseases result from deterioration of neurons or their myelin sheath which over time will lead to dysfunction and disabilities resulting from this. They are crudely divided into two groups according to phenotypic effects, although these are not mutually exclusive:

conditions causing problems with movements, such as ataxia
conditions affecting memory and related to dementia

Some proteins, called prions, suffer post-translational modification(s) that change their shape so that they no longer perform their cellular functions and instead trigger equivalent modifications in normal proteins, thus creating a cascade of damage that eventually results in significant neurodegeneration. In humans, this can cause Creutzfeldt-Jakob disease or variant CJD (Mad Cow Disease).

Normally, neurodegeneration begins long before the patient experiences any symptoms. It can be months or years before any effect is felt. Symptoms are noticed when many cells die or cease to function and a part of the brain begins to fail.

Regulation, or production of microglia by the immune system, in a process of neuroinflammation, is currently being rigorously studied for its role in neurodegenerative diseases.

List of neurodegenerative diseases

Alcoholism
Alexander's disease
Alper's disease
Alzheimer's disease
Amyotrophic lateral sclerosis
Ataxia telangiectasia
Batten disease (also known as Spielmeyer-Vogt-Sjogren-Batten disease)
Bovine spongiform encephalopathy (BSE)
Canavan disease
Cockayne syndrome
Corticobasal degeneration
Creutzfeldt-Jakob disease
Frontotemporal lobar degeneration
Huntington's disease
HIV-associated dementia
Kennedy's disease
Krabbe's disease
Lewy body dementia
Machado-Joseph disease (Spinocerebellar ataxia type 3)
Multiple System Atrophy
Narcolepsy
Neuroborreliosis
Parkinson's disease
Pelizaeus-Merzbacher Disease
Pick's disease
Primary lateral sclerosis
Prion diseases
Progressive Supranuclear Palsy
Refsum's disease
Sandhoff's disease
Schilder's disease
Subacute combined degeneration of spinal cord secondary to Pernicious Anaemia
Spielmeyer-Vogt-Sjogren-Batten disease (also known as Batten disease)
Spinocerebellar ataxia (multiple types with varying characteristics)
Spinal muscular atrophy
Steele-Richardson-Olszewski disease
Tabes dorsalis

These diseases have their own characteristics which usually affect middle aged or older people. They usually worsen over time.

Treatment

Initial treatment is dependent on diagnosis of underlying disorder. At present there are few therapies for the wide range of neurodegenerative diseases. Treatment with L-dopa can inhibit symptoms of Parkinson's Disease for a short time, but then causes acceleration of the symptoms. Efforts are being made to develop therapies for Alzheimer's Disease that will stabilize cognitive function at the level existing at time of diagnosis and treatment.

Research is highly invested in stem cell technology and stem cell treatments, as well as Gene therapy.

Research is underway into Bio-Markers as part of an attempt to understand the progression of certain types of neurodegenerative disease. In theory, if relevant bio-markers were identified, people could be treated for such diseases prior to onset of symptoms, thus resulting in a significant extension of their normal functional lifespan. As yet, however, the science of bio-markers is in its infancy and consequently diagnosis of neurodegenerative disease tends to occur after the patient has already suffered the majority of the neural damages.