THAP1 Mutations and Dystonia Phenotypes: Genotype Phenotype Correlations

Department of Neurology, Faculty of Medicine University of Thessaly, Larissa, Greece. .
Movement Disorders (Impact Factor: 5.68). 09/2012; 27(10):1290-4. DOI: 10.1002/mds.25146
Source: PubMed


THAP1 mutations have been shown to be the cause of DYT6. A number of different mutation types and locations in the THAP1 gene have been associated with a range of severity and dystonia phenotypes, but, as yet, it has been difficult to identify clear genotype phenotype patterns. Here, we screened the THAP1 gene in a further series of dystonia cases and evaluated the mutation pathogenicity in this series as well as previously reported mutations to investigate possible phenotype-genotype correlations. THAP1 mutations have been identified throughout the coding region of the gene, with the greatest concentration of variants localized to the THAP1 domain. In the additional cases analyzed here, a further two mutations were found. No obvious, indisputable genotype-phenotype correlation emerged from these data. However, we managed to find a correlation between the pathogenicity of mutations, distribution, and age of onset of dystonia. THAP1 mutations are an important cause of dystonia, but, as yet, no clear genotype-phenotype correlations have been identified. Greater mutation numbers in different populations will be important and mutation-specific functional studies will be essential to identify the pathogenicity of the various THAP1 mutations. © 2012 Movement Disorder Society.

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Available from: Kailash Bhatia
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    • "Mutations in THAP1 (THanatos-associated protein domain-containing, Apoptosis-associated Protein 1) underlie human dystonia type 6 (DYT6) [1-4]. Since the initial reports, many mutations in THAP1 have been identified in association with both generalized and focal dystonias [5]. Thap1 is a zinc-finger transcription factor that belongs to a family of molecules including over 100 homologues and orthologues [6-10]. "
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    ABSTRACT: Mutations in THAP1 result in dystonia type 6, with partial penetrance and variable phenotype. The goal of this study was to examine the nature and expression pattern of the protein product(s) of the Thap1 transcription factor (DYT6 gene) in mouse neurons, and to study the regional and developmental distribution, and subcellular localization of Thap1 protein. The goal was accomplished via overexpression and knock-down of Thap1 in the HEK293T cell line and in mouse striatal primary cultures and western blotting of embryonic Thap1-null tissue. The endogenous and transduced Thap1 isoforms were characterized using three different commercially available anti-Thap1 antibodies and validated by immunoprecipitation and DNA oligonucleotide affinity chromatography. We identified multiple, novel Thap1 species of apparent Mr 32 kDa, 47 kDa, and 50¿52 kDa in vitro and in vivo, and verified the previously identified species at 29¿30 kDa in neurons. The Thap1 species at the 50 kDa size range was exclusively detected in murine brain and testes and were located in the nuclear compartment. Thus, in addition to the predicted 25 kDa apparent Mr, we identified Thap1 species with greater apparent Mr that we speculate may be a result of posttranslational modifications. The neural localization of the 50 kDa species and its nuclear compartmentalization suggests that these may be key Thap1 species controlling neuronal gene transcription. Dysfunction of the neuronal 50 kDa species may therefore be implicated in the pathogenesis of DYT6.
    Full-text · Article · Sep 2014
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    • "Among the genetic primary dystonias, craniocervical dystonia has been mainly described in the context of DYT6 caused by THAP1 (thanatos-associated protein 1) gene mutations. The mean age at onset in DYT6 is 24.4 years (range, 2-62 years),4 and the most common site of onset is the upper limb (47%) followed by cranial dystonia (25%), cervical dystonia (23%), and rarely leg dystonia (17%).4,5 In more than half of DYT6 patients, dystonia spreads to become generalized or multifocal, which contrasts our DYT24 patients.2,4–8 "
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    ABSTRACT: Genes causing primary dystonia are rare. Recently, pathogenic mutations in the anoctamin 3 gene (ANO3) have been identified to cause autosomal dominant craniocervical dystonia and have been assigned to the dystonia locus dystonia-24 (DYT24). Here, we expand on the phenotypic spectrum of DYT24 and provide demonstrative videos. Moreover, tremor recordings were performed, and back-averaged electroencephalography, sensory evoked potentials, and C-reflex studies were carried out in two individuals who carried two different mutations in ANO3. Ten patients from three families are described. The age at onset ranged from early childhood to the forties. Cervical dystonia was the most common site of onset followed by laryngeal dystonia. The characteristic feature in all affected individuals was the presence of tremor, which contrasts DYT24 from the typical DYT6 phenotype. Tremor was the sole initial manifestation in some individuals with ANO3 mutations, leading to misdiagnosis as essential tremor. Electrophysiology in two patients with two different mutations showed co-contraction of antagonist muscles, confirming dystonia, and a 6-Hz arm tremor at rest, which increased in amplitude during action. In one of the studied patients, clinically superimposed myoclonus was observed. The duration of the myoclonus was in the range of 250 msec at about 3 Hz, which is more consistent with subcortical myoclonus. In summary, ANO3 causes a varied phenotype of young-onset or adult-onset craniocervical dystonia with tremor and/or myoclonic jerks. Patients with familial cervical dystonia who also have myoclonus-dystonia as well as patients with prominent tremor and mild dystonia should be tested for ANO3 mutations. © 2014 International Parkinson and Movement Disorder Society.
    Full-text · Article · Jun 2014 · Movement Disorders
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    • "Mutations in the THAP domain have been associated with an earlier age of onset of dystonia and with a more extensive anatomical distribution.14 However, several studies indicate that there is little evidence to date of any correlation between phenotype and genotype.15 Low penetrance may explain sporadic cases, including a case in our study (C). "
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    ABSTRACT: Several genes associated with dystonia have been identified. A mutation in one of these, THAP1 (DYT6), is linked to isolated dystonia. The aim of this study was to assess the prevalence of THAP1 gene mutations and the clinical characteristics of patients with these mutations in a clinical population in Brazil. Seventy-four patients presenting with dystonia involving the cervical muscles and without mutations in the TOR1A (DYT1) gene or any other movement disorders were recruited at a movement disorders clinic between June 2008 and June 2009. All the patients underwent clinical examination and were screened for mutations of the THAP1 gene. Three patients had the novel p.Gln97Ter THAP1 nonsense mutation in heterozygosis. One of them had no family history of dystonia. Symptoms in this patient first appeared in his right arm, and the condition progressed to the generalized form. The other two patients belonged to the same family (cousins). Symptoms in the first patient started in her right arm at the age of 18 years and the condition progressed to the segmental form. The second patient, who carried the p.Arg169Gln missense mutation, developed dystonia in her left arm at the age of 6 years. The condition progressed to generalized dystonia. We conclude that THAP1 mutations are also a cause, albeit uncommon, of segmental and generalized dystonia in the Brazilian population.
    Full-text · Article · Apr 2014
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