Assessment of D216H DYT1 polymorphism in a Chinese primary dystonia patient cohort

Association of TOR1A and GCH1 Polymorphisms with Isolated Dystonia in India

Isolated dystonia is a common movement disorder often caused by genetic mutations, although it is predominantly sporadic in nature. Common variants of dystonia-related genes were reported to be risk factors for idiopathic isolated dystonia. In this study, we aimed to analyse the roles of previously reported GTP cyclohydrolase (GCH1) and Torsin family 1 member A (TOR1A) polymorphisms in an Indian isolated dystonia case-control group. A total of 292 sporadic isolated dystonia patients and 316 control individuals were genotyped for single-nucleotide polymorphisms (SNPs) of GCH1 (rs3759664:G > A, rs12147422:A > G and rs10483639:C > G) and TOR1A (rs13300897:G > A, rs1801968:G > C, rs1182:G > T and rs3842225:G > Δ) using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and confirmed by direct Sanger sequencing. The statistical significance of allelic, genotypic and haplotypic associations of all of the SNPs were evaluated using the two-tailed Fisher exact test. The minor allele (A) of rs3759664 is significantly associated with isolated limb dystonia as a risk factor (p = 0.005). The minor allele (C) of rs1801968 is strongly associated with isolated dystonia (p < 0.0001) and most of its subtypes. The major allele of rs3842225 (G) may act as a significant risk factor for Writer's cramp (p = 0.03). Four different haplogroups comprising of either rs1182 or rs3842225 or in combination with rs1801968 and rs13300897 were found to be significantly associated with isolated dystonia. No other allelic, genotypic or haplotypic association was found to be significant with isolated dystonia cohort or its endophenotype stratified groups. Our study suggests that TOR1A common variants have a significant role in isolated dystonia pathogenesis in the Indian population, whereas SNPs in the GCH1 gene may have a limited role.

Risk Factor Genes in Patients with Dystonia: A Comprehensive Review

Background

Dystonia is a movement disorder with high heterogeneity regarding phenotypic appearance and etiology that occurs in both sporadic and familial forms. The etiology of the disease remains unknown. However, there is increasing evidence suggesting that a small number of gene alterations may lead to dystonia. Although pathogenic variants to the familial type of dystonia have been extensively reviewed and discussed, relatively little is known about the contribution of single-nucleotide polymorphisms (SNPs) to dystonia. This review focuses on the potential role of SNPs and other variants in dystonia susceptibility.

Methods

We searched the PubMed database for peer-reviewed articles published in English, from its inception through January 2018, that concerned human studies of dystonia and genetic variants. The following search terms were included: “dystonia” in combination with the following terms: 1) “polymorphisms” and 2) “SNPs” as free words.

Results

A total of 43 published studies regarding TOR1A, BDNF, DRD5, APOE, ARSG, NALC, OR4X2, COL4A1, TH, DDC, DBH, MAO, COMT, DAT, GCH1, PRKRA, MR-1, SGCE, ATP1A3, TAF1, THAP1, GNAL, DRD2, HLA-DRB, CBS, MTHFR, and MS genes, were included in the current review.

Discussion

To date, a few variants, which are possibly involved in several molecular pathways, have been related to dystonia. Large cohort studies are needed to determine robust associations between variants and dystonia with adjustment for other potential cofounders, in order to elucidate the pathogenic mechanisms of dystonia and the net effect of the genes.

The Role of TOR1A Polymorphisms in Dystonia: A Systematic Review and Meta-Analysis

Importance

A number of genetic loci were found to be associated with dystonia. Quite a few studies have been contacted to examine possible contribution of TOR1A variants to the risk of dystonia, but their results remain conflicting. The aim of the present study was to systematically evaluate the effect of TOR1A gene SNPs on dystonia and its phenotypic subtypes regarding the body distribution.

Methods

We performed a systematic review of Pubmed database to identify all available studies that reported genotype frequencies of TOR1A SNPs in dystonia. In total 16 studies were included in the quantitative analysis. Odds ratios (ORs) were calculated in each study to estimate the influence of TOR1A SNPs genotypes on the risk of dystonia. The fixed-effects model and the random effects model, in case of high heterogeneity, for recessive and dominant mode of inheritance as well as the free generalized odds ratio (OR_G) model were used to calculate both the pooled point estimate in each study and the overall estimates.

Results

Rs1182 was found to be associated with focal dystonia in recessive mode of inheritance [Odds Ratio, OR (95% confidence interval, C.I.): 1.83 (1.14–2.93), Pz = 0.01]. In addition, rs1801968 was associated with writer’s cramp in both recessive and dominant modes [OR (95%C.I.): 5.99 (2.08–17.21), Pz = 0.00009] and [2.48 (1.36–4.51), Pz = 0.003) respectively and in model free-approach [OR_G (95%C.I.): 2.58 (1.45–4.58)].

Conclusions

Our meta-analysis revealed a significant implication of rs1182 and rs1801968 TOR1A variants in the development of focal dystonia and writer’s cramp respectively. TOR1A gene variants seem to be implicated in dystonia phenotype.

Lack of association between TOR1A and THAP1 mutations and sporadic adult-onset primary focal dystonia in a Chinese population

OBJECTIVE

TOR1A (torsin family 1, member A) and THAP1 (THAP domain containing, apoptosis associated protein 1) are two candidate genes that have been reported to be linked to adult-onset primary dystonia. However, the overall results have been inconsistent, likely because primary dystonia may have subtype-specific genetic risk factors. The aim of our study was to assess the association of TOR1A and THAP1 with adult-onset primary focal dystonia (AOPFD), the most common subtype of primary dystonia.

METHODS

A total of 248 subjects, comprising 117 AOPFD patients and 131 healthy controls, were included in our study. All coding exons of TOR1A and THAP1 were initially analyzed in the 117 patients. Subsequently, we investigated the association of two common TOR1A variants (rs2296793, rs1801968) with AOPFD in a Chinese population (117 patients versus 131 controls) and performed a pooled analysis by combining our data with previously published data.

RESULTS

No mutation of TOR1A and THAP1 was found other than two TOR1A variants (rs2296793, rs1801968), which have been previously reported in AOPFD patients. There were no statistically significant differences in the minor allele frequency (MAF) and genotype frequency between AOPFD and controls in our Chinese population (P>0.05). This result was confirmed by pooled analysis of multi-ethnic groups.

CONCLUSION

Our study suggested that there might not be an association between TOR1A or THAP1 and patients with AOPFD.

Association analysis of TOR1A polymorphisms rs2296793 and rs3842225 in a Chinese population with cervical dystonia

BACKGROUND

TOR1A (torsinA, DYT1) is the leading cause of early-onset generalized dystonia, however, the associations between common TOR1A single nucleotide polymorphisms (SNPs) and primary adult-onset focal dystonia are controversial.

METHODS

In a cohort of 201 focal cervical dystonia (CD) patients, we genotyped rs2296793 and rs3842225 SNPs in TOR1A using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis. We also included 289 unrelated, age- and sex-matched healthy controls (HCs) from the same region.

RESULT

No significant differences were found in either the genotype distributions or minor allele frequencies (MAFs) of rs2296793 and rs3842225 between CD patients and HCs. There were no significant differences between early-onset and late-onset CD patients, between patients with and without a positive family history of dystonia, or between patients with and without tremor or sensory tricks.

CONCLUSION

Our study suggests that the common rs2296793 and rs3842225 SNPs of TOR1A do not play a major role in CD in a Chinese population.

TOR1A polymorphisms in a Russian cohort with primary focal/segmental dystonia

PURPOSE/AIM OF THE STUDY

To analyze contribution of rs3842225 and rs1182 single nucleotide polymorphisms (SNP) in TOR1A gene, the causative gene for the DYT1 form of hereditary early-onset generalized dystonia, to the development of focal and segmental dystonia in Russian patients.

MATERIALS AND METHODS

We analyzed associations between rs3842225 and rs1182 polymorphisms in TOR1A and focal/segmental dystonia in 254 patients from Russian population, including 218 Slavic patients and 36 patients of mixed ethnic background.

RESULTS

Stratification of patients based on age at the disease onset (≤ 30 years and > 30 years) showed statistically significant prevalence of the del-allele at the rs3842225 locus in Slavic patients with earlier age of onset of dystonia (36.96% vs. 21.39% in patients with late age of onset, p = 0.002) and an overrepresentation of the T-allele at the rs1182 locus (36.96% vs. 21.69%, p = 0.003). In Slavs, we also observed an overrepresentation of the homozygous genotypes, T/T (general sample of dystonia, 9.17% and focal dystonia, 10.28%) or G/G (general sample of dystonia, 60.55% and focal dystonia, 58.86%), compared to controls (T/T, 4.27% and G/G, 55.49%). In non-Slavic patients, we revealed neither significant associations, nor statistical tendencies regarding any of the clinical features.

CONCLUSIONS

Our data in an Eastern Slavic (Russian) population correspond well to results of other studies from different countries and confirm that certain TOR1A genotypes may be regarded as factors predisposing to focal and segmental dystonia.

Analysis of D216H polymorphism in Argentinean patients with primary dystonia

The D216H polymorphism (rs1801968) in TOR1A has been suggested as a risk factor for developing primary dystonia in German subjects not carrying the deletion c.904-906delGAG (∆GAG). However, this association could not be confirmed in other populations with different ethnic backgrounds. The purpose of this study is to evaluate the D216H polymorphism in an Argentinean cohort of 40 patients with primary dystonia and 200 unrelated control subjects. The authors could observe a significantly higher frequency of the H216 variant in dystonic patients lacking ∆GAG as compared with controls.

Association of rs1182 polymorphism of the DYT1 gene with primary dystonia in Chinese population

BACKGROUND

The deletion mutation of glutamate codon (GAG) in the TOR1A gene is a major cause of primary generalized dystonia. Recent genetic studies suggest that the rs1182 polymorphism in the same gene may represent a risk factor for primary dystonia. However, this finding has been inconsistent. Furthermore, no data on such an association in a Chinese population have been published.

METHODS

A total of 291 patients with primary dystonia from the Department of Neurology, West China Hospital of Sichuan University were included. From the same region, 294 healthy individuals were recruited as a control group. The SNP was identified by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

In the present study, focal dystonia was the most common presented form. No difference was found in the genotype frequency, minor allele frequencies, and "G" allele frequency between all dystonia patients and controls. No difference was found either, between early- and late-onset dystonia patients, patients with and without a positive family history, patients with pain and without pain, and patients with and without sensory trick. Moreover, no significant differences in the genotype and allele frequencies were found among different dystonia subtypes.

CONCLUSION

No association of the rs1182 of TOR1A with Chinese primary dystonia was found. More studies on such an association involving a larger number of participants, especially from Asian populations, are needed to confirm the present findings.

Botulinum toxin clinic-based epidemiologic survey of adults with primary dystonia in East china

Background and Purpose:

Primary focal or segmental dystonia is a rare clinical condition. The clinical features of dystonia have not been evaluated in China. We performed a study to investigate the epidemiology of primary dystonia and its clinical variants in an adult population.

Methods:

A Botulinum Toxin Clinic-based study was conducted in the period 18 May through 8 October 2010 in East China. We identified 523 dystonia patients from the Movement disorders and Botulinum Toxin clinic Cases.

Results:

The most common focal dystonia were blepharospasm (59%), cervical dystonia (35%), limb dystonia (3%), oromandibular dystonia (2%) and laryngeal dystonia (1%). Males with primary dystonia were noted to have earlier age of onset. A female predominance was noted for most of the primary dystonias with a male to female ratio (M : F) ranging from 1 : 1.48 to 1 : 3.

Conclusions:

The epidemiological features of dystonia in East China we collected were similar to the report in Japan which contrasts partly with that reported in Europe.

Common polymorphisms in dystonia-linked genes and susceptibility to the sporadic primary dystonias

Genes involved in familial dystonia syndromes (DYT genes) are ideal candidates for investigating whether common genetic variants influence the susceptibility to sporadic primary dystonia. To date, there have been few candidate gene studies for primary dystonia and only two DYT genes, TOR1A and THAP1, have been assessed. We therefore employed a haplotype-tagging strategy to comprehensively assess if common polymorphisms in eight DYT genes (TOR1A, TAF1, GCH1, THAP1, MR-1 (PNKD), SGCE, ATP1A3 and PRKRA) confer risk for sporadic primary dystonia. The 230 primary dystonia cases were matched for age and gender to 228 controls, recruited from movement disorder clinics in Brisbane, Australia and the Australian electoral roll. All subjects were genotyped for 56 tagging SNPs and genotype associations were investigated. Modest genotypic associations (P<0.05) were observed for three GCH1 SNPs (rs12147422, rs3759664 and rs10483639) when comparing all cases against controls. Associations were also seen when the cases were stratified based on presentation. Overall, our findings do not support the hypothesis that common TOR1A variants affect susceptibility for sporadic primary dystonia, and that it is unlikely that common variants around the DYT genes confer substantial risk for sporadic primary dystonia. Further work is warranted to follow up the GCH1 SNPs and the subgroup analyses.