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Amyotrophic lateral sclerosis-12 with or without frontotemporal dementia (ALS12) is a neurodegenerative disorder characterized by onset of ALS in adulthood. Rare patients may also develop frontotemporal dementia (FTD). Autosomal dominant and autosomal recessive inheritance patterns have been reported; there is also sporadic occurrence (summary by Maruyama et al., 2010 and Feng et al., 2019). For a general phenotypic description and a discussion of genetic heterogeneity of amyotrophic lateral sclerosis, see ALS1 (105400). [from OMIM]

Quigley (1993) reviewed adult-onset primary open angle glaucoma, which combines a particular abnormal appearance of the optic disc (optic nerve head) with a slowly progressive loss of visual sensitivity. Many patients with glaucoma have intraocular pressures above the normal range, although this cannot be considered part of the definition of the disease, since some patients have normal intraocular pressures. Changes in the optic disc, either inherited or acquired, contribute to the development of the disorder, which leads to visual loss from increasing nerve fiber layer atrophy. Quigley et al. (1994) stated that POAG should be reviewed as a multifactorial disorder. Genetic Heterogeneity of Primary Open Angle Glaucoma Other forms of primary open angle glaucoma include GLC1A (137750), caused by mutation in the MYOC gene (601652) on chromosome 1q24; GLC1B (606689) on chromosome 2cen-q13; GLC1C (601682) on chromosome 3q21-q24; GLC1D (602429) on chromosome 8q23; GLC1F (603383), caused by mutation in the ASB10 gene (615054) on chromosome 7q36; GLC1G (609887), caused by mutation in the WDR36 gene (609669) on chromosome 5q22; GLC1H (611276), caused by mutation in the EFEMP1 gene (601548) on chromosome 2p16; GLC1I (609745) on chromosome 15q11-q13; GLC1J (608695) on chromosome 9q22; GLC1K (608696) on chromosome 20p12; GLC1L (see 137750) on chromosome 3p22-p21; GLC1M (610535) on chromosome 5q22; GLC1N (611274) on chromosome 15q22-q24; GLC1O (613100), caused by mutation in the NTF4 gene (162662) on chromosome 19q13; GLC1P (177700), caused by an approximately 300-kb duplication on chromosome 12q24, most likely involving the TBK1 gene (604834). Nail-patella syndrome (NPS; 161200), which is caused by mutation in the LMX1B gene (602575) on chromosome 9q34, has open angle glaucoma as a pleiotropic feature. Other Forms of Glaucoma For a general description and a discussion of genetic heterogeneity of congenital forms of glaucoma, see GLC3A (231300). See 606657 for a discussion of normal tension glaucoma (NTG) or normal pressure glaucoma (NPG), a subtype of POAG. See 618880 for a discussion of primary closed-angle glaucoma. [from OMIM]

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.

There 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.

The 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.

Approximately 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.

A 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. [from MedlinePlus Genetics]