MedGen

Frontotemporal dementia (FTD) refers to a clinical manifestation of the pathologic finding of frontotemporal lobar degeneration (FTLD). FTD, the most common subtype of FTLD, is a behavioral variant characterized by changes in social and personal conduct with loss of volition, executive dysfunction, loss of abstract thought, and decreased speech output. A second clinical subtype of FTLD is 'semantic dementia,' characterized by specific loss of comprehension of language and impaired facial and object recognition. A third clinical subtype of FTLD is 'primary progressive aphasia' (PPA), characterized by a reduction in speech production, speech errors, and word retrieval difficulties resulting in mutism and an inability to communicate. All subtypes have relative preservation of memory, at least in the early stages. FTLD is often associated with parkinsonism or motor neuron disease (MND) resembling amyotrophic lateral sclerosis (ALS; 105400) (reviews by Tolnay and Probst, 2002 and Mackenzie and Rademakers, 2007). Mackenzie et al. (2009, 2010) provided a classification of FTLD subtypes according to the neuropathologic findings (see PATHOGENESIS below). Clinical Variability of Tauopathies Tauopathies comprise a clinically variable group of neurodegenerative diseases characterized neuropathologically by accumulation of abnormal MAPT-positive inclusions in nerve and/or glial cells. In addition to frontotemporal dementia, semantic dementia, and PPA, different clinical syndromes with overlapping features have been described, leading to confusion in the terminology (Tolnay and Probst, 2002). Other terms used historically include parkinsonism and dementia with pallidopontonigral degeneration (PPND) (Wszolek et al., 1992); disinhibition-dementia-parkinsonism-amyotrophy complex (DDPAC) (Lynch et al., 1994); frontotemporal dementia with parkinsonism (FLDEM) (Yamaoka et al., 1996); and multiple system tauopathy with presenile dementia (MSTD) (Spillantini et al., 1997). These disorders are characterized by variable degrees of frontal lobe dementia, parkinsonism, motor neuron disease, and amyotrophy. Other neurodegenerative associated with mutations in the MAPT gene include Pick disease (172700) and progressive supranuclear palsy (PSP; 601104), Inherited neurodegenerative tauopathies linked to chromosome 17 and caused by mutation in the MAPT gene have also been collectively termed 'FTDP17' (Lee et al., 2001). Kertesz (2003) suggested the term 'Pick complex' to represent the overlapping syndromes of FTD, primary progressive aphasia (PPA), corticobasal degeneration (CBD), PSP, and FTD with motor neuron disease. He noted that frontotemporal dementia may also be referred to as 'clinical Pick disease' and that the term 'Pick disease' should be restricted to the pathologic finding of Pick bodies. Genetic Heterogeneity of Frontotemporal Lobar Degeneration Mutations in several different genes can cause frontotemporal dementia and frontotemporal lobar degeneration, with or without motor neuron disease. See FTLD with TDP43 inclusions (607485), caused by mutation in the GRN gene (138945) on chromosome 17q21; FTLALS7 (600795), caused by mutation in the CHMP2B gene (609512) on chromosome 3p11; inclusion body myopathy with Paget disease and FTD (IBMPFD; 167320), caused by mutation in the VCP gene (601023) on chromosome 9p13; ALS6 (608030), caused by mutation in the FUS gene (137070) on 16p11; ALS10 (612069), caused by mutation in the TARDBP gene (605078) on 1p36; and FTDALS1 (105550), caused by mutation in the C9ORF72 gene (614260) on 9p21. In 1 family with FTD, a mutation was identified in the presenilin-1 gene (PSEN1; 104311) on chromosome 14, which is usually associated with a familial form of early-onset Alzheimer disease (AD3; 607822). [from OMIM]

The spectrum of GRN frontotemporal dementia (GRN-FTD) includes the behavioral variant (bvFTD), primary progressive aphasia (PPA; further subcategorized as progressive nonfluent aphasia [PNFA] and semantic dementia [SD]), and movement disorders with extrapyramidal features such as parkinsonism and corticobasal syndrome (CBS). A broad range of clinical features both within and between families is observed. The age of onset ranges from 35 to 87 years. Behavioral disturbances are the most common early feature, followed by progressive aphasia. Impairment in executive function manifests as loss of judgment and insight. In early stages, PPA often manifests as deficits in naming, word finding, or word comprehension. In late stages, affected individuals often become mute and lose their ability to communicate. Early findings of parkinsonism include rigidity, bradykinesia or akinesia (slowing or absence of movements), limb dystonia, apraxia (loss of ability to carry out learned purposeful movements), and disequilibrium. Late motor findings may include myoclonus, dysarthria, and dysphagia. Most affected individuals eventually lose the ability to walk. Disease duration is three to 12 years. [from GeneReviews]

C9orf72 frontotemporal dementia and/or amyotrophic lateral sclerosis (C9orf72-FTD/ALS) is characterized most often by frontotemporal dementia (FTD) and upper and lower motor neuron disease (MND); however, atypical presentations also occur. Age at onset is usually between 50 and 64 years (range: 20-91 years) irrespective of the presenting manifestations, which may be pure FTD, pure amyotrophic lateral sclerosis (ALS), or a combination of the two phenotypes. The clinical presentation is highly heterogeneous and may differ between and within families, causing an unpredictable pattern and age of onset of clinical manifestations. The presence of MND correlates with an earlier age of onset and a worse overall prognosis. [from GeneReviews]

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. There is evidence this disease is caused by heterozygous mutation in the TARDBP gene that encodes the TDP43 protein on chromosome 1p36. [from SNOMEDCT_US]

Generally, Parkinson's disease that begins after age 50 is called late-onset disease. The condition is described as early-onset disease if signs and symptoms begin before age 50. Early-onset cases that begin before age 20 are sometimes referred to as juvenile-onset Parkinson's disease.

Parkinson's disease can also affect emotions and thinking ability (cognition). Some affected individuals develop psychiatric conditions such as depression and visual hallucinations. People with Parkinson's disease also have an increased risk of developing dementia, which is a decline in intellectual functions including judgment and memory.

Often the first symptom of Parkinson's disease is trembling or shaking (tremor) of a limb, especially when the body is at rest. Typically, the tremor begins on one side of the body, usually in one hand. Tremors can also affect the arms, legs, feet, and face. Other characteristic symptoms of Parkinson's disease include rigidity or stiffness of the limbs and torso, slow movement (bradykinesia) or an inability to move (akinesia), and impaired balance and coordination (postural instability). These symptoms worsen slowly over time.

Parkinson's disease is a progressive disorder of the nervous system. The disorder affects several regions of the brain, especially an area called the substantia nigra that controls balance and movement. [from MedlinePlus Genetics]

CHMP2B frontotemporal dementia (CHMP2B-FTD) has been described in a single family from Denmark, in one individual with familial FTD from Belgium, and in one individual with FTD and no family history. It typically starts between ages 46 and 65 years with subtle personality changes and slowly progressive behavioral changes, dysexecutive syndrome, dyscalculia, and language disturbances. Disinhibition or loss of initiative is the most common presenting symptom. The disease progresses over a few years into profound dementia with extrapyramidal symptoms and mutism. Several individuals have developed an asymmetric akinetic rigid syndrome with arm and gait dystonia and pyramidal signs that may be related to treatment with neuroleptic drugs. Symptoms and disease course are highly variable. Disease duration may be as short as three years or longer than 20 years. [from GeneReviews]

Inclusion body myopathy associated with Paget disease of bone (PDB) and/or frontotemporal dementia (IBMPFD) is characterized by adult-onset proximal and distal muscle weakness (clinically resembling a limb-girdle muscular dystrophy syndrome), early-onset PDB, and premature frontotemporal dementia (FTD). Muscle weakness progresses to involve other limb and respiratory muscles. PDB involves focal areas of increased bone turnover that typically lead to spine and/or hip pain and localized enlargement and deformity of the long bones; pathologic fractures occur on occasion. Early stages of FTD are characterized by dysnomia, dyscalculia, comprehension deficits, and paraphasic errors, with minimal impairment of episodic memory; later stages are characterized by inability to speak, auditory comprehension deficits for even one-step commands, alexia, and agraphia. Mean age at diagnosis for muscle disease and PDB is 42 years; for FTD, 56 years. Dilated cardiomyopathy, amyotrophic lateral sclerosis, and Parkinson disease are now known to be part of the spectrum of findings associated with IBMPFD. [from GeneReviews]

Pick disease refers to the neuropathologic finding of 'Pick bodies,' which are argyrophilic, intraneuronal inclusions, and 'Pick cells,' which are enlarged neurons. The clinical correlates of Pick disease of brain include those of frontotemporal dementia, which encompass the behavioral variant of FTD, semantic dementia, and progressive nonfluent aphasia (summary by Piguet et al., 2011). Kertesz (2003) suggested the term 'Pick complex' to represent the overlapping syndromes of FTD, primary progressive aphasia (PPA), corticobasal degeneration (CBD), progressive supranuclear palsy (601104), and FTD with motor neuron disease. He noted that frontotemporal dementia may also be referred to as 'clinical Pick disease,' and that the term 'Pick disease' should be restricted to the pathologic finding of Pick bodies. [from OMIM]

The spectrum of DCTN1-related neurodegeneration includes Perry syndrome, distal hereditary motor neuronopathy type 7B (dHMN7B), frontotemporal dementia (FTD), motor neuron disease / amyotrophic lateral sclerosis (ALS), and progressive supranuclear palsy. Some individuals present with overlapping phenotypes (e.g., FTD-ALS, Perry syndrome-dHMN7B). Perry syndrome (the most common of the phenotypes associated with DCTN1) is characterized by parkinsonism, neuropsychiatric symptoms, hypoventilation, and weight loss. The mean age of onset in those with Perry syndrome is 49 years (range: 35-70 years), and the mean disease duration is five years (range: 2-14 years). In most affected persons, the reported cause/circumstance of death relates to sudden death/hypoventilation or suicide. [from GeneReviews]

Any amyotrophic lateral sclerosis in which the cause of the disease is a mutation in the UBQLN2 gene. [from MONDO]

CHCHD10-related disorders are characterized by a spectrum of adult-onset neurologic phenotypes that can include: Mitochondrial myopathy (may also be early onset): weakness, amyotrophy, exercise intolerance. Amyotrophic lateral sclerosis (ALS): progressive degeneration of upper motor neurons and lower motor neurons. Frontotemporal dementia (FTD): slowly progressive behavioral changes, language disturbances, cognitive decline, extrapyramidal signs. Late-onset spinal motor neuronopathy (SMA, Jokela type): weakness, cramps, and/or fasciculations; areflexia. Axonal Charcot-Marie-Tooth neuropathy: slowly progressive lower-leg muscle weakness and atrophy, small hand muscle weakness, loss of tendon reflexes, sensory abnormalities. Cerebellar ataxia: gait ataxia, kinetic ataxia (progressive loss of coordination of lower- and upper-limb movements), dysarthria/dysphagia, nystagmus, cerebellar oculomotor disorder. Because of the recent discovery of CHCHD10-related disorders and the limited number of affected individuals reported to date, the natural history of these disorders (except for SMAJ caused by the p.Gly66Val pathogenic variant) is largely unknown. [from GeneReviews]

Frontotemporal dementia and/or amyotrophic lateral sclerosis-3 is an autosomal dominant neurodegenerative disorder characterized by adult or late adult onset of cognitive impairment, behavioral abnormalities, and speech apraxia and/or upper and lower motor neuron signs. Some patients may also develop Paget disease of bone. The phenotype is highly variable, even within families (summary by Rea et al., 2014). For a discussion of genetic heterogeneity of FTDALS, see FTDALS1 (105550). [from OMIM]

Inclusion body myopathy associated with Paget disease of bone (PDB) and/or frontotemporal dementia (IBMPFD) is characterized by adult-onset proximal and distal muscle weakness (clinically resembling a limb-girdle muscular dystrophy syndrome), early-onset PDB, and premature frontotemporal dementia (FTD). Muscle weakness progresses to involve other limb and respiratory muscles. PDB involves focal areas of increased bone turnover that typically lead to spine and/or hip pain and localized enlargement and deformity of the long bones; pathologic fractures occur on occasion. Early stages of FTD are characterized by dysnomia, dyscalculia, comprehension deficits, and paraphasic errors, with minimal impairment of episodic memory; later stages are characterized by inability to speak, auditory comprehension deficits for even one-step commands, alexia, and agraphia. Mean age at diagnosis for muscle disease and PDB is 42 years; for FTD, 56 years. Dilated cardiomyopathy, amyotrophic lateral sclerosis, and Parkinson disease are now known to be part of the spectrum of findings associated with IBMPFD. [from GeneReviews]

Frontotemporal dementia and/or amyotrophic lateral sclerosis-4 is an autosomal dominant neurodegenerative disorder characterized by adult or late adult onset of cognitive impairment, behavioral abnormalities, and speech apraxia and/or upper and lower motor neuron signs. The phenotype is highly variable (summary by Freischmidt et al., 2015). For a discussion of genetic heterogeneity of FTDALS, see FTDALS1 (105550). [from OMIM]

Any amyotrophic lateral sclerosis in which the cause of the disease is a mutation in the TUBA4A gene. [from MONDO]

Frontotemporal dementia and/or amyotrophic lateral sclerosis-8 (FTDALS8) is an autosomal dominant neurodegenerative disorder characterized by adult-onset dementia manifest as memory impairment, executive dysfunction, and behavioral or personality changes. Some patients may develop ALS or parkinsonism. Neuropathologic studies show frontotemporal lobar degeneration (FTLD) with tau (MAPT; 157140)- and TDP43 (605078)-immunoreactive inclusions (summary by Dobson-Stone et al., 2020). For a discussion of genetic heterogeneity of FTDALS, see FTDALS1 (105550). [from OMIM]

Amyotrophic lateral sclerosis-26 with or without frontotemporal dementia (ALS26) is an autosomal dominant neurodegenerative disorder characterized by adult onset of upper and low motor neuron disease causing bulbar dysfunction and limb weakness (ALS). Patients may also develop frontotemporal dementia (FTD) manifest as primary progressive aphasia, memory impairment, executive dysfunction, and behavioral or personality changes. Although patients may present with 1 or the other diseases, all eventually develop ALS. Neuropathologic studies of the brain and spinal cord show TDP43 (605078)-immunoreactive cytoplasmic inclusions that correlate with clinical features and Lewy body-like cytoplasmic inclusions in lower motor neurons (summary by Mackenzie et al., 2017). For a discussion of genetic heterogeneity of amyotrophic lateral sclerosis, see ALS1 (105400). [from OMIM]

Frontotemporal dementia and/or amyotrophic lateral sclerosis-5 (FTDALS5) is an autosomal dominant neurodegenerative disorder characterized by onset of ALS or FTD symptoms in adulthood. The disease is progressive, and some patients may develop both diseases, although ALS seems to be more prevalent than FTD. The disorder usually results in premature death (summary by Williams et al., 2016). For a discussion of genetic heterogeneity of FTDALS, see FTDALS1 (105550). [from OMIM]