ALS
Rare neurodegenerative disease causing progressive motor neuron loss.
Amyotrophic lateral sclerosis (ALS), also called motor neuron disease (MND) or Lou Gehrig's disease, is a rare and terminal neurodegenerative condition. It involves the steady loss of both upper and lower motor neurons—the cells that control voluntary muscle movement. ALS is the most common type of motor neuron disease. Early signs often include gradual muscle stiffness, twitching, weakness, and wasting. As motor neurons continue to die, people typically lose the ability to eat, speak, move, and breathe without help from machines. At least half of those with ALS experience notable changes in thinking and behavior, and about 15% go on to develop frontotemporal dementia. Diagnosis relies on a person’s symptoms and tests to rule out other conditions. Depending on where symptoms start, ALS can be classified as limb-onset (weakness in arms or legs), bulbar-onset (trouble speaking or swallowing), or respiratory-onset (breathing difficulty), which occurs in about 1–3% of cases.
Most cases—roughly 90–95%—have no known cause and are called sporadic ALS. Genetic, autoimmune, and environmental factors are thought to play a role. About 5–10% of cases have a known genetic cause and are often linked to family history; these are called familial or hereditary ALS. The most common genetic cause in familial cases is a mutation in the C9orf72 gene, which also appears in some sporadic cases. Four disease-linked genes account for about half of all genetic cases.
There is no cure for ALS. Treatment aims to slow the disease and ease symptoms. Two FDA-approved drugs, riluzole and edaravone, can slow progression. Non-invasive ventilation can improve both quality and length of life. Mechanical ventilation extends survival but does not stop the disease. A feeding tube can help maintain weight and nutrition. Death usually results from respiratory failure. ALS can strike at any age but typically begins around age 60. Average survival from onset is two to four years, though about 10% of people live longer than ten years.
The earliest known description of ALS is often attributed to Charles Bell in an 1830 publication. In 1869, French neurologist Jean-Martin Charcot first linked the symptoms to underlying neurological problems, and by 1874 he began using the term amyotrophic lateral sclerosis.
**Classification**
ALS is a motor neuron disease, a group of disorders that selectively affe
- field
- Neurology
- known_for
- Progressive loss of motor neurons leading to muscle weakness, paralysis, and respiratory failure
- first_described
- 1830 by Charles Bell
- neurological_link_established
- 1869 by Jean-Martin Charcot
- term_coined
- 1874 by Jean-Martin Charcot
- average_survival
- Two to four years from onset
- typical_age_of_onset
- Around age 60
Lore & Background
The earliest known description of ALS is often attributed to Charles Bell in an 1830 publication. In 1869, the connection between the symptoms and the underlying neurological problems was first described by French neurologist Jean-Martin Charcot, who in 1874 began using the term amyotrophic lateral sclerosis. Most cases (about 90–95%) have no known cause and are known as sporadic ALS, while approximately 5–10% have a known genetic cause and are often linked to a family history of ALS. Mutations in the C9orf72 gene are the most common known genetic cause of familial ALS and are also found in a subset of sporadic cases. Primary lateral sclerosis (PLS) is a distinct motor neuron disease, not a subtype of ALS.
Reader's Guide
ALS is significant as a terminal neurodegenerative disease that affects both upper and lower motor neurons, leading to progressive loss of voluntary muscle control. The disease typically presents with gradual muscle stiffness, twitches, weakness, and wasting, and at least 50% of people with ALS experience significant changes in thinking and behavior, with 15% developing frontotemporal dementia. There is no known cure; FDA-approved treatments riluzole and edaravone slow progression, while non-invasive ventilation improves quality and length of life. The average survival from onset to death is two to four years, though about 10% survive longer than ten years. ALS can be classified by onset type—limb-onset (about two-thirds of classical cases), bulbar-onset (about 25%), or respiratory-onset (1–3% of cases)—and by genetic origin. The disease's complexity and overlapping subtypes present challenges to diagnosis, understanding, and prognosis.
Did You Know?
- At least 50% of people with ALS experience significant changes in thinking and behavior, with 15% developing frontotemporal dementia.
- Mutations in the C9orf72 gene are the most common known genetic cause of familial ALS and are also found in a subset of sporadic cases.
- About 10% of all cases of ALS begin before age 45, and about 1% begin before age 25.
- Primary lateral sclerosis (PLS) accounts for about 5% of all ALS cases and has a better prognosis than classical ALS.
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