Spinocerebellar ataxia type 11 (SCA11): An update.

Spinocerebellar ataxias, also called autosomal dominant cerebellar ataxias, are a group of neurological genetic diseases characterised by chronic, progressive cerebellar ataxia. The clinical hallmark of spinocerebellar ataxia is the loss of balance and coordination, accompanied by slurred speech. Spinocerebellar ataxia type 11 is a rare subtype of spinocerebellar ataxia caused by mutations in the tau tubulin kinase 2 gene. Patients with spinocerebellar ataxia are clinically characterised by slowly progressive cerebellar ataxia, trunk and limb ataxia, and eye movement abnormalities with occasional pyramidal features. Peripheral neuropathy and dystonia are rare. According to the literature, only nine families affected with spinocerebellar ataxia have been reported worldwide. Herein, a series of spinocerebellar ataxia cases are discussed in detail to determine the potential research direction of this dysfunction, including its epidemiology, clinical features, genetic characteristics, diagnosis and differential diagnosis, pathogenic mechanisms, treatment, prognosis, follow-up, genetic counselling and future perspectives, and to improve the overall understanding of spinocerebellar ataxia among clinicians, researchers and patients.

The Chinese Parkinson's Disease Registry (CPDR): Study Design and Baseline Patient Characteristics.

BACKGROUND: There is a lack of large multicenter Parkinson's disease (PD) cohort studies and limited data on the natural history of PD in China. OBJECTIVES: The objective of this study was to launch the Chinese Parkinson's Disease Registry (CPDR) and to report its protocol, cross-sectional baseline data, and prospects for a comprehensive observational, longitudinal, multicenter study. METHODS: The CPDR recruited PD patients from 19 clinical sites across China between January 2018 and December 2020. Clinical data were collected prospectively using at least 17 core assessment scales. Patients were followed up for clinical outcomes through face-to-face interviews biennially. RESULTS: We launched the CPDR in China based on the Parkinson's Disease & Movement Disorders Multicenter Database and Collaborative Network (PD-MDCNC). A total of 3148 PD patients were enrolled comprising 1623 men (51.6%) and 1525 women (48.4%). The proportions of early-onset PD (EOPD, age at onset ≤50 years) and late-onset PD (LOPD) were 897 (28.5%) and 2251 (71.5%), respectively. Stratification by age at onset showed that EOPD manifested milder motor and nonmotor phenotypes and was related to increased probability of dyskinesia. Comparison across genders suggested a slightly older average age at PD onset, milder motor symptoms, and a higher rate of developing levodopa-induced dyskinesias in women. CONCLUSIONS: The CPDR is one of the largest multicenter, observational, longitudinal, and natural history studies of PD in China. It offers an opportunity to expand the understanding of clinical features, genetic, imaging, and biological markers of PD progression. © 2022 International Parkinson and Movement Disorder Society.

Sensitivity of Sniffer Dogs for a Diagnosis of Parkinson's Disease: A Diagnostic Accuracy Study.

BACKGROUND: The diagnostic criteria for Parkinson's disease (PD) remain complex, which is especially problematic for nonmovement disorder experts. A test is required to establish a diagnosis of PD with improved accuracy and reproducibility. OBJECTIVE: The study aimed to investigate the sensitivity and specificity of tests using sniffer dogs to diagnose PD. METHODS: A prospective, diagnostic case-control study was conducted in four tertiary medical centers in China to evaluate the accuracy of sniffer dogs to distinguish between 109 clinically established medicated patients with PD, 654 subjects without PD, 37 drug-naïve patients with PD, and 185 non-PD controls. The primary outcomes were sensitivity and specificity of sniffer dog's identification. RESULTS: In the study with patients who were medicated, when two or all three sniffer dogs yielded positive detection results in a sample tested, the index test sensitivity, specificity, and positive and negative likelihood ratios were 91% (95% CI: 84%-96%), 95% (95% CI: 93%-97%), and 19.16 (95% CI: 13.52-27.16) and 0.10 (95% CI: 0.05-0.17), respectively. The corresponding sensitivity, specificity, and positive and negative likelihood ratios in patients who were drug-naïve were 89% (95% CI: 75%-96%), 86% (95% CI: 81%-91%), and 6.6 (95% CI: 4.51-9.66) and 0.13 (95% CI: 0.05-0.32), respectively. CONCLUSIONS: Tests using sniffer dogs may be a useful, noninvasive, fast, and cost-effective method to identify patients with PD in community screening and health prevention checkups as well as in neurological practice. © 2022 International Parkinson and Movement Disorder Society.

Mutation analysis of MFSD8 in an amyotrophic lateral sclerosis cohort from mainland China.

Recent studies have suggested that rare variants in MFSD8 contribute to risk for frontotemporal dementia (FTD). Considering the common underlying pathogenesis and the shared genetic risk between amyotrophic lateral sclerosis (ALS) and FTD, we screened the coding region of MFSD8 in 551 unrelated patients with ALS (510 unrelated sporadic ALS and 41 familial ALS probands) from mainland China by whole-exome sequencing to assess its mutation frequency in patients with ALS and evaluate its association. Two rare deleterious variants, c.343G>A (p. V115M) and c.695T>C (p.L232P), were identified in this study. The variant c.695T>C (p.L232P) has not been previously reported and the carrier of this variant exhibits a relatively younger age of disease onset. Our studies provide some independent evidence showing that the rare variant p.L232P in MFSD8 might be a candidate risk factor for ALS. However, the relatively small sample size and the lack of patient-derived cells limit the power of the genetic exploration of this study, further robust multicenter studies with larger sizes and biological experiments with patient-derived cells are needed to elucidate the pathogenesis of the rare variant in MFSD8 in ALS.

Expansion of GGC repeat in the human-specific NOTCH2NLC gene is associated with essential tremor.

Essential tremor is one of the most common movement disorders. Despite its high prevalence and heritability, the genetic aetiology of essential tremor remains elusive. Up to now, only a few genes/loci have been identified, but these genes have not been replicated in other essential tremor families or cohorts. Here we report a genetic study in a cohort of 197 Chinese pedigrees clinically diagnosed with essential tremor. Using a comprehensive strategy combining linkage analysis, whole-exome sequencing, long-read whole-genome sequencing, repeat-primed polymerase chain reaction and GC-rich polymerase chain reaction, we identified an abnormal GGC repeat expansion in the 5' region of the NOTCH2NLC gene that co-segregated with disease in 11 essential tremor families (5.58%) from our cohort. Clinically, probands that had an abnormal GGC repeat expansion were found to have more severe tremor phenotypes, lower activities of daily living ability. Obvious genetic anticipation was also detected in these 11 essential tremor-positive families. These results indicate that abnormal GGC repeat expansion in the 5' region of NOTCH2NLC gene is associated with essential tremor, and provide strong evidence that essential tremor is a family of diseases with high clinical and genetic heterogeneities.

The role of genetics in Parkinson's disease: a large cohort study in Chinese mainland population.

This study aimed to determine the mutational spectrum of familial Parkinson's disease and sporadic early-onset Parkinson's disease (sEOPD) in a mainland Chinese population and the clinical features of mutation carriers. We performed multiplex ligation-dependent probe amplification assays and whole-exome sequencing for 1676 unrelated patients with Parkinson's disease in a mainland Chinese population, including 192 probands from families with autosomal-recessive Parkinson's disease, 242 probands from families with autosomal-dominant Parkinson's disease, and 1242 sEOPD patients (age at onset ≤ 50). According to standards and guidelines from the American College of Medical Genetics and Genomics, pathogenic/likely pathogenic variants in 23 known Parkinson's disease-associated genes occurred more frequently in the autosomal-recessive Parkinson's disease cohort (65 of 192, 33.85%) than in the autosomal-dominant Parkinson's disease cohort (10 of 242, 4.13%) and the sEOPD cohort (57 of 1242, 4.59%), which leads to an overall molecular diagnostic yield of 7.88% (132 of 1676). We found that PRKN was the most frequently mutated gene (n = 83, 4.95%) and present the first evidence of an SNCA duplication and LRRK2 p.N1437D variant in mainland China. In addition, several novel pathogenic/likely pathogenic variants including LRRK2 (p.V1447M and p.Y1645S), ATP13A2 (p.R735X and p.A819D), FBXO7 (p.G67E), LRP10 (c.322dupC/p.G109Rfs*51) and TMEM230 (c.429delT/p.P144Qfs*2) were identified in our cohort. Furthermore, the age at onset of the 132 probands with genetic diagnoses (median, 31.5 years) was about 14.5 years earlier than that of patients without molecular diagnoses (i.e. non-carriers, median 46.0 years). Specifically, the age at onset of Parkinson's disease patients with pathogenic/likely pathogenic variants in ATP13A2, PLA2G6, PRKN, or PINK1 was significantly lower than that of non-carriers, while the age at onset of carriers with other gene pathogenic/likely pathogenic variants was similar to that of non-carriers. The clinical spectrum of Parkinson's disease-associated gene carriers in this mainland Chinese population was similar to that of other populations. We also detected 61 probands with GBA possibly pathogenic variants (3.64%) and 59 probands with GBA p.L444P (3.52%). These results shed insight into the genetic spectrum and clinical manifestations of Parkinson's disease in mainland China and expand the existing repertoire of pathogenic or likely pathogenic variants involved in known Parkinson's disease-associated genes. Our data highlight the importance of genetic testing in Parkinson's disease patients with age at onset < 40 years, especially in those from families with a recessive inheritance pattern, who may benefit from early diagnosis and treatment.

The Expanding Phenotypic Spectrums Associated with ATP1A3 Mutation in a Family with Rapid-Onset Dystonia Parkinsonism.

INTRODUCTION: Rapid-onset dystonia parkinsonism (RDP), also referred to as Dystonia 12, is a rare autosomal dominant genetic disease characterized by abrupt onset of a rostrocaudal gradient of dystonia with prominent bulbar symptoms, and parkinsonian features, primarily bradykinesia and postural instability without tremor. The purpose of this study was to identify the genetic defect in a Chinese pedigree with familial RDP and to explore genotype-phenotype correlation. METHODS: A 3-generation Chinese Han pedigree consisting of 9 members and 3 patients with RDP, and 200 unrelated ethnically matched normal subjects were recruited in this study. Exome sequencing was performed in the proband, and Sanger sequencing was then conducted in other family members and 200 normal controls. RESULTS: In addition to the typical clinical manifestations of RDP, the proband and her sister presented tongue tremor which developed at the onset, and intriguingly the proband showed a "re-emergent" tongue tremor. Both the proband and her sister had a medical history of hyperthyroidism, and at the psychiatric interview they both received diagnoses of depression and anxiety. Excessive grammar errors existed in most sentences written by the proband, and this written-expression disorder occurred years before the onset of RDP. The mother of the proband presented tongue enlargement, oromandibular dystonia, and limb dystonia, which were not observed in her 2 daughters at the time of study. A missense variant, c.1838C>T (p.T613M), in the ATP1A3 gene, was identified in the 3 patients in the family and in 2 young children but was absent in family members without RDP and in the 200 normal controls. CONCLUSION: These findings may broaden the phenotypic spectrums of RDP with mutations in the ATP1A3 gene, provide new insights into the diagnosis of RDP, and have implications for genetic counseling.

Reliability and validity of the Chinese version of the Short Musculoskeletal Function Assessment questionnaire in patients with skeletal muscle injury of the upper or lower extremities.

BACKGROUND: The Short Musculoskeletal Function Assessment (SMFA) questionnaire is one of the most commonly used scales to evaluate functional status and quality of life (QOL) of patients with a broad range of musculoskeletal disorders. However, a Chinese version of the SMFA questionnaire for the psychometric properties of skeletal muscle injury patients in China is still lacking. The current study translated the SMFA into Chinese and assessed its reliability and validity among Chinese patients with skeletal muscle injury of the upper or lower extremities. METHODS: The original SMFA was translated from English into Chinese and culturally adapted according to cross-cultural adaptation guidelines. A multicenter cross-sectional study was conducted, comprising 339 skeletal muscle injury patients (aged 20-75 years) from 4 hospitals. The SMFA, the health survey short form (SF-36) along with a region-specific questionnaire (including the disabilities of the arm, shoulder, and hand questionnaire (DASH), the hip disability and osteoarthritis outcome score (HOOS), the knee injury and osteoarthritis outcome score (KOOS), and the foot function index (FFI)) were completed according to the region of injury. Reliability was estimated from the internal consistency using Cronbach's α and validity was assessed via convergent validity, known-groups comparison, and construct validity. RESULTS: Cronbach's α coefficient was over 0.75 for two subscales and four categories of the SMFA, suggesting that the internal consistency reliability of the SMFA was satisfactory. Known-groups comparison showed that the dysfunction index and the bother index of the SMFA discriminated well between patients who differed in age, gender, injury location, and operation status rather than in subgroups based on the body mass index (BMI). The convergent validity of the SMFA was good, as moderate to excellent correlations were found between the subscales of the SMFA and the four subscales of SF-36 (physical function, role-physical, bodily pain, and social functioning) and the region-specific questionnaires. The construct validity was proved by the presence of a six-factor structure that accounted for 66.85 % of the variance. CONCLUSION: The Chinese version of the SMFA questionnaire is a reliable and valid instrument to measure patient-reported impact of musculoskeletal injuries in the upper or lower extremities.

Characteristics of fatigue in Parkinson's disease: A longitudinal cohort study.

Objective: To assess the prevalence, evolution, clinical characteristics, correlates and predictors of fatigue as well as to investigate the influence of comorbid fatigue on the longitudinal changes in motor and non-motor symptoms over a 2-year longitudinal follow-up period in a large cohort of patients with Parkinson's disease (PD). Materials and methods: A total of 2,100 PD patients were enrolled from the Parkinson's Disease & Movement Disorders Multicenter Database and Collaborative Network in China (PD-MDCNC), and their motor and non-motor symptoms were assessed biennially using comprehensive scales, including the 16-item Parkinson Fatigue Scale (PFS-16). Each PD patient was categorized as PD with or without fatigue on the basis of a cut-off mean PFS-16 score of 3.3. Results: The prevalence of fatigue in our cohort was 36.8%. Compared to PD patients without fatigue, PD patients with fatigue were more likely to be older, have a longer disease duration, and higher baseline levodopa equivalent daily dose (all p < 0.05). Moreover, PD patients with fatigue showed more severe motor and non-motor phenotypes than those without fatigue. Overall, high total Unified Parkinson's Disease Rating Scale (UPDRS) score (odds ratio [OR] = 1.016, 95% confidence interval [CI]: 1.009-1.024), Non-Motor Symptoms Scale score (OR = 1.022, 95% CI: 1.015-1.029), postural instability and gait difficulty (PIGD) subtype (OR = 1.586, 95% CI: 1.211-2.079), presence of excessive daytime sleepiness (EDS; OR = 1.343, 95% CI: 1.083-1.666), and wearing-off (OR = 1.282, 95% CI: 1.023-1.607) were significantly associated with fatigue in PD patients (all p < 0.05). High total UPDRS score at baseline (OR = 1.014, 95% CI: 1.002-1.027, p = 0.028) increased the risk of developing fatigue during follow-up. Although significant, the odds ratios were low and confidence intervals were narrow. Analysis of disease progression showed significant group differences in motor and non-motor symptoms. In comparison with the never-fatigue group, the persistent-fatigue group showed significantly greater progression in motor, autonomic dysfunction, sleep, depression and cognitive symptoms (all p < 0.05). Conclusion: Increased disease severity, presence of the PIGD subtype, EDS, and wearing-off were associated with fatigue in PD patients. Significant subgroup-level differences were observed in the progression of motor and non-motor symptoms across different fatigue subgroups of PD patients.

Age and Sex Affect Essential Tremor (ET) Plus: Clinical Heterogeneity in ET Based on the National Survey in China.

The new term essential tremor (ET) plus was proposed in the 2018 tremor consensus criteria. The National Survey of Essential Tremor Plus in China, a large multicenter registry study, aimed to evaluate the clinical features of pure ET and ET plus and explore possible factors related to ET plus. All patients with ET underwent neurological examination and neuropsychological assessment at 17 clinical sites. The diagnosis was made according to the 2018 consensus criteria. Clinicodemographic characteristics were analyzed. A total of 1160 patients were included, including 546 patients with pure ET and 614 patients with ET plus. The proportion of females was significantly higher in the ET plus than that in the pure ET (P = 0.001). The age at onset (AAO) of pure ET showed a bimodal distribution, with peaks in the 2nd and 5th decades. However, the AAO of the ET plus group demonstrated a skewed distribution, with a single peak in the 6th decade. Female sex (OR=1.645, P<0.001), older age (OR=1.023, P<0.001), lower educational level (OR=0.934, P<0.001), head tremor (OR=1.457, P<0.001), and higher the Tremor Research Group Essential Tremor Rating Assessment Scale (TETRAS)-II scores (OR=1.134, P<0.001) were significantly associated with ET plus. Old age and female sex may contribute to ET plus development. Pure ET showed a bimodal distribution for AAO, whereas ET plus showed a unimodal distribution. It remains unclear whether pure ET and ET plus are merely different stages of a single disease or represent distinct disease entities.

Genome-wide association study using whole-genome sequencing identifies risk loci for Parkinson's disease in Chinese population.

Genome-wide association studies (GWASs) have identified numerous susceptibility loci for Parkinson's disease (PD), but its genetic architecture remains underexplored in populations of non-European ancestry. To identify genetic variants associated with PD in the Chinese population, we performed a GWAS using whole-genome sequencing (WGS) in 1,972 cases and 2,478 controls, and a replication study in a total of 8209 cases and 9454 controls. We identified one new risk variant rs61204179 (Pcombined = 1.47 × 10-9) with low allele frequency, four previously reported risk variants (NUCKS1/RAB29-rs11557080, SNCA-rs356182, FYN-rs997368, and VPS13C-rs2251086), as well as three risk variants in LRRK2 coding region (A419V, R1628P, and G2385R) with genome-wide significance (P < 5 × 10-8) for PD in Chinese population. Moreover, of the reported genome-wide significant risk variants found mostly in European ancestry populations, the correlation coefficient (rb) of effect size accounting for sampling errors was 0.91 between datasets and 63.6% attained P < 0.05 in Chinese population. Accordingly, we estimated a heritability of 0.14-0.18 for PD, and a moderate genetic correlation between European ancestry and Chinese populations (rg = 0.47, se = 0.21). Polygenic risk score (PRS) analysis revealed that individuals with PRS values in the highest quartile had a 3.9-fold higher risk of developing PD than the lowest quartile. In conclusion, the present GWAS identified PD-associated variants in Chinese population, as well as genetic factors shared among distant populations. Our findings shed light on the genetic homogeneity and heterogeneity of PD in different ethnic groups and suggested WGS might continue to improve our understanding of the genetic architecture of PD.

Subtyping of early-onset Parkinson's disease using cluster analysis: A large cohort study.

Background: Increasing evidence suggests that early-onset Parkinson's disease (EOPD) is heterogeneous in its clinical presentation and progression. Defining subtypes of EOPD is needed to better understand underlying mechanisms, predict disease course, and eventually design more efficient personalized management strategies. Objective: To identify clinical subtypes of EOPD, assess the clinical characteristics of each EOPD subtype, and compare the progression between EOPD subtypes. Materials and methods: A total of 1,217 patients were enrolled from a large EOPD cohort of the Parkinson's Disease & Movement Disorders Multicenter Database and Collaborative Network in China (PD-MDCNC) between January 2017 and September 2021. A comprehensive spectrum of motor and non-motor features were assessed at baseline. Cluster analysis was performed using data on demographics, motor symptoms and signs, and other non-motor manifestations. In 454 out of total patients were reassessed after a mean follow-up time of 1.5 years to compare progression between different subtypes. Results: Three subtypes were defined: mild motor and non-motor dysfunction/slow progression, intermediate and severe motor and non-motor dysfunction/malignant. Compared to patients with mild subtype, patients with the severe subtype were more likely to have rapid eye movement sleep behavior disorder, wearing-off, and dyskinesia, after adjusting for age and disease duration at baseline, and showed a more rapid progression in Unified Parkinson's Disease Rating Scale (UPDRS) total score (P = 0.002), UPDRS part II (P = 0.014), and III (P = 0.001) scores, Hoehn and Yahr stage (P = 0.001), and Parkinson's disease questionnaire-39 item version score (P = 0.012) at prospective follow-up. Conclusion: We identified three different clinical subtypes (mild, intermediate, and severe) using cluster analysis in a large EOPD cohort for the first time, which is important for tailoring therapy to individuals with EOPD.

Related factors of ICARS and SARA scores on spinocerebellar ataxia type 3/Machado-Joseph disease.

OBJECTIVE: To investigate the related factors of international cooperative ataxia rating scale (ICARS) and scale for the assessment and rating of ataxia scores (SARA) in patients with spinocerebellar ataxia type 3/Machado-Joseph disease. METHODS: A total of 126 SCA3/MJD patients were assessed by ICARS and SARA. The relation between ICARS or SARA scores and age of onset, disease duration and CAG repeat size was analyzed. RESULTS: Either the total ICARS or the total SARA score was positively related with the disease duration(r=0.586,P<0.05;r=0.643,P<0.05). Simple linear regression equations were: Y(1)(total ICARS score)=13.072+2.388 X(2)(disease duration)(F=68.874,P<0.05); Y(2)(total SARA score)=4.403+ 0.961 X(2)(disease duration)(F=87.254, P<0.05). Either age adjusted the total ICARS score or age adjusted the total SARA score was positively related with CAG repeat size(r=0.328, P<0.05; r=0.335, P<0.05). Both the ICARS subscores and the SARA subscores were positively related with the disease duration(r=0.257-0.589, P<0.05; r=0.432-0.623, P<0.05). Both age adjusted ICARS subscores and age adjusted SARA subscores were positively related with CAG repeat size(r=0.263-0.403, P<0.05; r=0.189-0.366, P<0.05). Analysis of variance showed that the total ICARS score and the total SARA score increased with the disease stage. CONCLUSION: ICARS and SARA are both reliable and effective scales in assessing the severity of ataxia in patients with SCA3/MJD, and researchers can choose the most suitable scale according to specific requirement.

Serum concentrations of NSE and S100B in spinocerebellar ataxia type 3/Machado-Joseph disease.

OBJECTIVE: To determine the neuronal damage or loss and gliosis at the cellular level in spinocerebellar ataxia type 3/Machado-Joseph disease(SCA3/MJD), and evaluate the potential use of neuron-specific enolase (NSE) and protein S 100 B(S100B) serum concentrations as biochemical markers. METHODS: Serum concentrations of NSE and S100B were measured in 102 SCA3/MJD patients and 100 healthy subjects matched by sex and age. The correlations between both markers and age, age of onset, disease duration, CAG repeat size, scores of international cooperative ataxia rating scale(ICARS), and scale for the assessment and rating of ataxia(SARA) were analyzed. RESULTS: Compared with the healthy controls, patients with SCA3/MJD had higher NSE serum concentrations [(6.95 ± 2.83)ng/mL vs (4.83 ± 1.70) ng/mL, P<0.05] and higher S100B serum concentrations [(0.07 ± 0.06) ng/mL vs (0.05 ± 0.02) ng/mL, P<0.05]. In the SCA3/MJD patients group, NSE levels presented a positive correlation with age, disease duration, ICARS scores and SARA scores, whereas S100B levels did not correlate with age, age of onset, disease duration, ICARS scores and SARA scores. CAG repeat size did not correlate with the NSE levels and S100B levels in different age groups of SCA3/MJD patients. CONCLUSION: Serum NSE might be a useful marker to monitor disease progression and represent the degree of severity of a certain disease. Elevated S100B serum concentrations in patients compared to healthy controls may suggest an application of this protein as a peripheral marker of brain impairment in SCA3/MJD.

Spinocerebellar ataxias in mainland China: an updated genetic analysis among a large cohort of familial and sporadic cases.

OBJECTIVE: To undertake an updated genetic spectrum analysis in patients with hereditary spinocerebellar ataxia (SCA) in mainland China. METHODS: SCA 1, 2, 3, 6, 7, 8, 10, 12, 17 and dentatorubral-pallidoluysian atrophy (DRPLA) nucleotide repeat mutations were detected in 430 families with autosomal dominant SCA (ADCA) and 237 patients with sporadic ataxias by PCR and DNA sequencing. Subsequently, point and Indel (Insertion/deletion) mutation analyses of SCA5, SCA11, SCA13, SCA14, SCA15/16/29, SCA27, SCA31 and SCA35 were detected in 91 families with ADCA and 196 patients with sporadic ataxias excluded from SCA1, 2, 3, 6, 7, 8, 10, 12, 17 and DRPLA genotypes via PCR and Denaturing High Performance Liquid Chromatography (PCR-DHPLC), Multiplex ligation-dependent probe amplification and DNA direct sequencing analysis. RESULTS: Among the 430 ADCA families, there were 25 SCA1 (5.81%), 27 SCA2 (6.28%), 267 SCA3/MJD (62.09%), 8 SCA6 (1.86%), 8 SCA7 (1.86%), 1 SCA12 (0.23%), 1 SCA17 (0.23%) and 2 SCA35 (0.47%), and the remaining 91 families (21.16%) were genetically unidentified. Among the 237 sporadic SCA patients, there were 6 SCA1 (2.53%), 9 SCA2 (3.80%), 23 SCA3/MJD (9.70%) and 3 SCA6 (1.27%), and the remaining 196 (82.7%) were genetically unidentified. No pathogenic point mutation causing SCA5, SCA11, SCA13, SCA14, SCA27 or SCA31 subtypes was found. CONCLUSION: SCA3/MJD is substantially the most common subtype in patients with ADCA and sporadic forms in mainland China, followed by SCA2, SCA1, SCA6 and SCA7. While SCA12, SCA17 and SCA35 are seldom found, SCA5, SCA8, SCA10, SCA11, SCA13, SCA27, SCA31 and DRPLA are very rare. The high proportion of genetically unidentified cases further verify that SCAs are of highly genetic heterogeneity, suggesting that other disease-causing genes might be involved in the negative ADCA pedigrees, and other etiological factors may involve in those sporadic cases other than genetics.

Magnetic resonance spectroscopy of the cerebellum in patients with spinocerebellar ataxia type 3/Machado-Joseph disease.

OBJECTIVE: To evaluate the metabolite pattern and the severity in patients with spinocerebellar ataxia type 3/ Machado-Joseph disease (SCA3/MJD) by (1)H magnetic resonance spectroscopy ((1)H-MRS) on different cerebellar regions, including cerebellar vermis, cerebellar peduncles, cerebellar cortex, and dentatum. METHODS: Thirty-six SCA3/MJD patients, and 27 sex, age-matched healthy controls were scanned with (1)H-MRS for N-acetylaspartate (NAA), choline (Cho) and creatine (Cr). We made cerebellar vermis, cerebellar peduncles, cerebellar cortex, and dentatum as the region of interests (ROI), and finally got access to NAA/Cr, Cho/Cr, and NAA/Cho ratios. We also examined the CAG repeat numbers of MJD1 gene, scored the 36 patients by the scale for the assessment and rating of ataxia (SARA), analyzed the differences in ratios between SCA3/MJD patients and the control group, and explored whether relevance existed between these ratios and duration of the disease, age of onset, CAG repeat times, and SARA scores respectively. RESULTS: The ratio of NAA/Cr in SCA3/MJD patients showed a significant reduction in the cerebellar cortex, dentatum, cerebellar vermis and medipeduncle (P<0.01) compared with the controls. The ratio of NAA/Cho also showed significant reduction in the dentatum and cerebellar vermis (P<0.01). A number of correlations were found between the metabolite ratios of (1)H-MRS and duration of the disease, age of onset, expanded CAG and SARA score in SCA3/MJD patients. CONCLUSION: (1)H-MRS, which shows the neural metabolic changes in the cerebella of SCA3/MJD patients, provides useful information about the severity of SCA3/MJD.

Spinocerebellar ataxia type 11 in the Chinese Han population.

The spinocerebellar ataxias (SCAs) are a clinically and genetically heterogeneous group of neurodegenerative diseases. Researchers have recently found that SCA type 11 (SCA11) is associated with mutations in the TTBK2 gene. In our previous work, we performed mutation detection in SCA1, 2, 3, 6, 7, 8, 10, 12, 17 and dentatorubral-pallidoluysian atrophy gene in Chinese SCA patients, but the genes responsible for approximately 40% of our patients have not yet been identified. To investigate the frequency of SCA11 in Chinese SCA patients, we examined the TTBK2 gene in 68 unrelated probands diagnosed with dominantly inherited ataxia using the denaturing high-performance liquid chromatography method. All analyzed samples displayed the normal elution profile, which denoted that no disease-related mutation was identified. We provided the evidence that SCA11 is a rare form of ataxia in China.