Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027066 (myoclonus)
 4,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Corticobasal syndrome (CBS) is a clinical syndrome presenting with progressive asymmetric bradykinesia, rigidity, and dystonia accompanied by cortical signs, such as apraxia, alien limb phenomena, cortical sensory loss, myoclonus, and mirror movements. CBS is associated with different pathological conditions including FTLD-tau (corticobasal degeneration, CBD; progressive supranuclear palsy, PSP: and Pick disease), FTLD-TDP, Alzheimer disease, Creutzfeldt-Jakob disease, and Parkinson disease/dementia with Lewy bodies. Among these, the most common pathology is CBD. In patients with familial and sporadic FTLD, MAPT, GRN and C9orf72 mutations are the three main causes of the disease, even though the C9orf72 mutation is rare in Japan. Patients with MAPT mutations present with FTLD-tau, and patients with GRN and C9orf72 mutations exhibit FTLD-TDP. FTLD is also associated with VCP, CHMP2B, TARDBP and FUS mutations, but each of these account for <1% of familial FTLD cases. In sporadic cases, the H1c haplotype and the rare p.A152T variant of MAPT are known to be associated with FTLD-tau, and the common genetic variant (rs5848) in the 3'-UTR of GRN is associated with FTLD-TDP. A recent genome-wide association study identified TMEM106B as a potential risk-modifying factor for FTLD-TDP, and STX6, EIF2AK3 and MOBP, for PSP. Despite major advances in genetic studies in recent years, the majority of sporadic CBS cases are genetically unsolved. Further studies are needed to unveil the genetic background of CBS. In this review, we discuss the recent advances related to the genetics of CBS, particularly about the genetics of FTLD.
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PMID:[The genetics of corticobasal syndrome]. 2330 Jan

Mutations in seven genes are robustly associated with autosomal dominant (SNCA, LRRK2, EIF4G1, VPS35) or recessive (parkin/PARK2, PINK1, DJ1/PARK7) Parkinson's disease (PD) or parkinsonism. Changes in a long list of additional genes have been suggested as causes for parkinsonism or PD, including genes for hereditary ataxias (ATXN2, ATXN3, FMR1), frontotemporal dementia (C9ORF72, GRN, MAPT, TARDBP), DYT5 (GCH1, TH, SPR), and others (ATP13A2, CSF1R, DNAJC6, FBXO, GIGYF2, HTRA2, PLA2G6, POLG, SPG11, UCHL1). This review summarizes the clinical features of diseases caused by mutations in these genes, and their frequencies. Point mutations and multiplications in SNCA cause cognitive or psychiatric symptoms, parkinsonism, dysautonomia and myoclonus with widespread alpha-synuclein pathology in the central and peripheral nervous system. LRRK2 mutations may lead to a clinical phenotype closely resembling idiopathic PD with a puzzling variety in neuropathology. Mutations in parkin/PARK2, PINK1 or DJ1/PARK7 may cause early-onset parkinsonism with a low risk for cognitive decline and a pathological process usually restricted to the brainstem. Carriers of mutations in the other genes may develop parkinsonism with or without additional symptoms, but rarely a disease resembling PD. The pathogenicity of several mutations remains unconfirmed. Although some mutations occur with high frequency in specific populations, worldwide all are very rare. The genetic cause of the majority of patients with sporadic or hereditary PD remains unknown in most populations. Clinical genetic testing is useful for selected patients. Testing strategies need to be adapted individually based on clinical phenotype and estimated frequency of the mutation in the patient's population.
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PMID:Monogenic Parkinson's disease and parkinsonism: clinical phenotypes and frequencies of known mutations. 2346 81

Frontotemporal dementia (FTD) refers to a group of clinically and genetically heterogeneous neurodegenerative disorders that are a common cause of adult-onset behavioural and cognitive impairment. FTD often presents in combination with various hyperkinetic or hypokinetic movement disorders, and evidence suggests that various genetic mutations underlie these different presentations. Here, we review the known syndromatic-genetic correlations in FTD. Although no direct genotype-phenotype correlations have been identified, mutations in multiple genes have been associated with various presentations. Mutations in the genes that encode microtubule-associated protein tau (MAPT) and progranulin (PGRN) can manifest as symmetrical parkinsonism, including the phenotypes of Richardson syndrome and corticobasal syndrome (CBS). Expansions in the C9orf72 gene are most frequently associated with familial FTD, typically combined with motor neuron disease, but other manifestations, such as symmetrical parkinsonism, CBS and multiple system atrophy-like presentations, have been described in patients with these mutations. Less common gene mutations, such as those in TARDBP, CHMP2B, VCP, FUS and TREM2, can also present as atypical parkinsonism. The most common hyperkinetic movement disorders in FTD are motor and vocal stereotypies, which have been observed in up to 78% of patients with autopsy-proven FTD. Other hyperkinetic movements, such as chorea, orofacial dyskinesias, myoclonus and dystonia, are also observed in some patients with FTD.
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PMID:Parkinsonism, movement disorders and genetics in frontotemporal dementia. 2689 67