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Amyotrophic lateral sclerosis type 6(ALS6)

MedGen UID:
Concept ID:
Disease or Syndrome
Synonyms: AMYOTROPHIC LATERAL SCLEROSIS 6 WITHOUT FRONTOTEMPORAL DEMENTIA; Amyotrophic lateral sclerosis 6, with or without frontotemporal dementia; FUS-Related Amyotrophic Lateral Sclerosis; FUS-Related Amyotrophic Laterial Sclerosis
SNOMED CT: Amyotrophic lateral sclerosis type 6 (1204334005); ALS6 - amyotrophic lateral sclerosis type 6 (1204334005)
Gene (location): FUS (16p11.2)
Monarch Initiative: MONDO:0011951
OMIM®: 608030


A neurodegenerative disease with characteristics of progressive muscular paralysis reflecting degeneration of motor neurons in the primary motor cortex, corticospinal tracts, brainstem and spinal cord. Caused by heterozygous mutation in the FUS gene on chromosome 16p11. [from SNOMEDCT_US]

Clinical features

From HPO
Amyotrophic lateral sclerosis
MedGen UID:
Concept ID:
Disease or Syndrome
Amyotrophic lateral sclerosis (ALS) is a progressive disease that affects motor neurons, which are specialized nerve cells that control muscle movement. These nerve cells are found in the spinal cord and the brain. In ALS, motor neurons die (atrophy) over time, leading to muscle weakness, a loss of muscle mass, and an inability to control movement.\n\nThere are many different types of ALS; these types are distinguished by their signs and symptoms and their genetic cause or lack of clear genetic association. Most people with ALS have a form of the condition that is described as sporadic, which means it occurs in people with no apparent history of the disorder in their family. People with sporadic ALS usually first develop features of the condition in their late fifties or early sixties. A small proportion of people with ALS, estimated at 5 to 10 percent, have a family history of ALS or a related condition called frontotemporal dementia (FTD), which is a progressive brain disorder that affects personality, behavior, and language. The signs and symptoms of familial ALS typically first appear in one's late forties or early fifties. Rarely, people with familial ALS develop symptoms in childhood or their teenage years. These individuals have a rare form of the disorder known as juvenile ALS.\n\nThe first signs and symptoms of ALS may be so subtle that they are overlooked. The earliest symptoms include muscle twitching, cramping, stiffness, or weakness. Affected individuals may develop slurred speech (dysarthria) and, later, difficulty chewing or swallowing (dysphagia). Many people with ALS experience malnutrition because of reduced food intake due to dysphagia and an increase in their body's energy demands (metabolism) due to prolonged illness. Muscles become weaker as the disease progresses, and arms and legs begin to look thinner as muscle tissue atrophies. Individuals with ALS eventually lose muscle strength and the ability to walk. Affected individuals eventually become wheelchair-dependent and increasingly require help with personal care and other activities of daily living. Over time, muscle weakness causes affected individuals to lose the use of their hands and arms. Breathing becomes difficult because the muscles of the respiratory system weaken. Most people with ALS die from respiratory failure within 2 to 10 years after the signs and symptoms of ALS first appear; however, disease progression varies widely among affected individuals.\n\nApproximately 20 percent of individuals with ALS also develop FTD. Changes in personality and behavior may make it difficult for affected individuals to interact with others in a socially appropriate manner. Communication skills worsen as the disease progresses. It is unclear how the development of ALS and FTD are related. Individuals who develop both conditions are diagnosed as having ALS-FTD.\n\nA rare form of ALS that often runs in families is known as ALS-parkinsonism-dementia complex (ALS-PDC). This disorder is characterized by the signs and symptoms of ALS, in addition to a pattern of movement abnormalities known as parkinsonism, and a progressive loss of intellectual function (dementia). Signs of parkinsonism include unusually slow movements (bradykinesia), stiffness, and tremors. Affected members of the same family can have different combinations of signs and symptoms.
MedGen UID:
Concept ID:
Sign or Symptom
Fasciculations are observed as small, local, involuntary muscle contractions (twitching) visible under the skin. Fasciculations result from increased irritability of an axon (which in turn is often a manifestation of disease of a motor neuron). This leads to sporadic discharges of all the muscle fibers controlled by the axon in isolation from other motor units.
Gait disturbance
MedGen UID:
Concept ID:
The term gait disturbance can refer to any disruption of the ability to walk. In general, this can refer to neurological diseases but also fractures or other sources of pain that is triggered upon walking. However, in the current context gait disturbance refers to difficulty walking on the basis of a neurological or muscular disease.
MedGen UID:
Concept ID:
Reduction of neurologic reflexes such as the knee-jerk reaction.
Neuronal loss in central nervous system
MedGen UID:
Concept ID:
Proximal amyotrophy
MedGen UID:
Concept ID:
Disease or Syndrome
Amyotrophy (muscular atrophy) affecting the proximal musculature.

Professional guidelines

Recent clinical studies


Assoni AF, Guerrero EN, Wardenaar R, Oliveira D, Bakker PL, Alves LM, Carvalho VM, Okamoto OK, Zatz M, Foijer F
Brain Pathol 2024 Jan;34(1):e13206. Epub 2023 Aug 15 doi: 10.1111/bpa.13206. PMID: 37582053Free PMC Article
Larner AJ, Fratalia L
Br J Hosp Med (Lond) 2019 Feb 2;80(2):110-111. doi: 10.12968/hmed.2019.80.2.110. PMID: 30746996


Bonet LFS, Loureiro JP, Pereira GRC, Da Silva ANR, De Mesquita JF
PLoS One 2021;16(9):e0258061. Epub 2021 Sep 29 doi: 10.1371/journal.pone.0258061. PMID: 34587215Free PMC Article

Clinical prediction guides

Bonet LFS, Loureiro JP, Pereira GRC, Da Silva ANR, De Mesquita JF
PLoS One 2021;16(9):e0258061. Epub 2021 Sep 29 doi: 10.1371/journal.pone.0258061. PMID: 34587215Free PMC Article

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