脊髓小脑性共济失调3型一家系的临床表现分析

目的 探讨1个脊髓小脑性共济失调3型(SCA3)家系中患者的临床表现,分析影响其特征、异质性及严重程度的原因。方法 采用PCR、琼脂糖凝胶电泳的方法对1个脊髓小脑性共济失调家系进行基因检测明确分型并获得等位基因内CAG三核苷酸重复扩增次数; 对比该家系中5例患者的典型症状、非典型症状,了解其临床异质性并分析产生原因。结果 确定该家系为脊髓小脑性共济失调SCA3型,发现3名表现正常的女性携带者。CAG重复次数与病程长短呈负相关(r=-0.942,P<0.05); 病程与共济失调严重程度呈正相关(r=1.000,0.913,P<0.01)。结论 该家系所有患者以明显共济失调及构音障碍为临床特征,特别是躯干及下肢的共济失调; CAG重复次数、病程及共济失调严重程度之间有明显相关性; 认知功能障碍随着疾病的进展逐渐显现; 眼肌麻痹、括约肌功能障碍或吞咽困难与CAG重复次数之间无明显关系但增加疾病持续时间; 锥体束受损及严重程度可能提示预后不良。     

HSP27 and cell death in spinocerebellar ataxia type 3

Spinocerebellar ataxia type 3 (SCA3) is an autosomal dominant spinocerebellar degeneration characterized by a wide range of clinical manifestations. In this review, we discuss the role(s) that heat shock protein 27 (HSP27) may play in the cell death process of spinocerebellar ataxia type 3.     

The impact of ethnicity on the clinical presentations of spinocerebellar ataxia type 3

BackgroundFor a variety of sporadic neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis, it is well-established that ethnicity does affect the disease phenotypes. However, how ethnicity contributes to the clinical symptoms and disease progressions in monogenetic disorders, such as spinocerebellar ataxia type 3 (SCA3), remains less studied.MethodsWe used multivariable linear and logistical regression models in 257 molecularly-confirmed SCA3 patients (66 Caucasians, 43 African Americans, and 148 Asians [composed of 131 Chinese and 17 Asian Americans]) to explore the influence of ethnicity on age at onset (AAO), ataxia severity, and non-ataxia symptoms (i.e. depression, tremor, and dystonia).ResultsWe found that Asians had significantly later AAO, compared to Caucasians (β = 4.75, p = 0.000) and to African Americans (β = 6.64, p = 0.000) after adjusting for the pathological CAG repeat numbers in ATXN3. African Americans exhibited the most severe ataxia as compared to Caucasians (β = 3.81, p = 0.004) and Asians (β = 4.39, p = 0.001) after taking into consideration of the pathological CAG repeat numbers in ATXN3 and disease duration. Caucasians had a higher prevalence of depression than African Americans (β = 1.23, p = 0.040). Ethnicity had no influence on tremor or dystonia.ConclusionsEthnicity plays an important role in clinical presentations of SCA3 patients, which could merit further clinical studies and public health consideration. These results highlight the role of ethnicity in monogenetic, neurodegenerative disorders.     

1例误诊为强直性肌营养不良的脊髓小脑共济失调3型患者的基因诊断

目的探讨基因诊断在临床误诊为强直性肌营养不良的3型遗传性脊髓小脑共济失调家系中的价值。方法收集家系成员外周血,提取基因组DNA,全基因组外显子测序筛查致病基因。PCR扩增患者遗传性脊髓小脑共济失调3型致病基因片段,电泳和测序鉴定异常电泳条带。结果基因诊断确诊该患者为遗传性脊髓小脑共济失调3型,并非强直性肌营养不良。该患者致病基因为杂合子,CAG重复次数分别为21次和71次。结论外显子组测序技术在孟德尔遗传病中寻找致病基因发挥了重要作用以及基因诊断对不典型脊髓小脑共济失调有很好的确诊价值,对于临床出现相类似的症状的患者或与其他疾病症状相叠加的脊髓小脑共济失调的患者,均应进行基因诊断,以免出现漏诊和误诊。     

The molecular diagnosis of spinocerebellar ataxia type 1 in patients with ataxia

Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant neurodegenerative disease caused by an expanded CAG trinucleotide repeat in the SCA1 gene on chromosome 6. We screened 40 probands with ataxia for the CAG repeat expansion and found five probands with SCA1 representing five different families. The SCA1 gene was analysed in 50 members of these families, and the CAG repeat expansion was found in all 17 affected persons and in 14 unaffected at-risk individuals. The range of expansion was 41–53 repeat units, while the range of normal alleles was 22–36 repeat units. We found pronounced inter- and intrafamilial phenotypical variation. One of the families had a comparatively mild phenotype which correlates with a CAG repeat length in the low end of the range of expansions and a late age at onset. With few exceptions, normal alleles of the SCA1 gene have one to three CAT interruptions in the middle of the CAG repeat, while all expanded alleles are uninterrupted. We report the hitherto longest normal uninterrupted allele of 22 repeat units and stress the importance of analysis for the presence of CAT interruptions in the diagnosis of SCA1.     

Symptom onset of spinocerebellar ataxia type 10 in pregnancy and puerperium

Spinocerebellar ataxia type 10 is an autosomal dominant neurodegenerative disorder. It was initially described in Mexican families presenting with ataxia and epilepsy, with or without polyneuropathy, pyramidal signs and cognitive symptoms. The authors report three patients from the same family who were asymptomatic until gestation and puerperium, when they developed symptoms and signs suggestive of the syndrome. Genetic diagnosis was made in the three patients. The authors hypothesize that hormonal changes are likely to influence the manifestation of the condition.     

Analysis of mitochondrial DNA variations in a Chinese family with spinocerebellar ataxia

Mitochondrial dysfunction and mitochondrial DNA (mtDNA) variations have been shown to have a role in several neurological diseases. To determine whether there is an association between mtDNA variations and spinocerebellar ataxia (SCA), we analyzed the mtDNA main control region (D-loop), as well as mtDNA content and the prevalence of the common deletion, in blood samples from members of a large Chinese family (14 individuals with SCA and 13 healthy individuals). All 14 individuals with SCA were genotyped as SCA3. Thirteen mtDNA haplotypes were identified among the 27 subjects. We detected no mutations in the mtDNA D-loop region and found no significant differences in mtDNA copy number or common deletion level between patients and their healthy relatives. Contrary to some previous reports, our study showed that mtDNA variations seem to be a rare event in individuals with SCA3.     

Estimation of skeletal muscle mass in patients with spinocerebellar ataxia type 3 and 10

Background: Neurodegenerative diseases may progress to a level in which patients present spontaneous weight loss, resulting in increased falls and functional disabilities when the disease is associated with muscle mass depletion.

Objective: Evaluate the muscle compartment in patients presenting spinocerebellar ataxia (SCA) type 3 and 10.

Methods: Forty-six patients presenting SCA type 3 and 10 were assessed and 76 volunteers were selected to the control group. In order to evaluate the muscle compartment, muscle mass anthropometric measurements were assessed and total skeletal muscle mass calculated through a predictive equation.

Results: Women with SCA3 presented greater weight loss and muscle mass reduction compared to those with SCA10 and the control group. Among the predictive measurements, calf muscle circumference showed a more significant correlation with total skeletal muscle mass (p = 0.718).

Conclusion: Patients presenting both types of ataxia did not show severe depletion in their nutritional status; however, those with SCA3 displayed greater weight loss and muscle mass reduction compared to the SCA10 group.     

脊髓小脑性共济失调3型一家系报道

目的 探讨脊髓小脑性共济失调(spinocerebellar ataxia, SCA)3型(SCA3)的临床特点。方法 收集1例2016年6月在济宁医学院附属医院神经内科住院的SCA3患者及其家系的临床资料,基因检测明确家系分型,结合文献分析家系中的临床差异。结果 患者23岁发病,临床表现为行走不稳伴进行性下肢无力,肌张力正常,水平性诱发眼震,无跌倒及吟诗性语言,闭目难立征阳性,呈宽基底步态,双侧巴氏征未引出,腹壁反射减低,膝反射及跟腱反射活跃,深浅感觉未见异常。基因检测提示患者ATXN3基因CAG重复次数79次(正常人范围在12～44次),超过正常范围,患者其它(ATXN1、ATXN2、CACNA1A、ATXN7、ATXN8、PPP2R2B、TBP)基因的CAG重复次数均在正常范围内。患者的55岁父亲、6岁女儿及4岁儿子的ATXN3基因的CAG重复数分别为65、73、71次,超过正常范围,但均未发病。患者母亲ATXN3基因的CAG重复数29次,属正常范围,未见临床症状。结论 本例家系是SCA3型,具有临床异质性,基因检测有助于诊断。     

Ataxin-7 expression analysis in controls and spinocerebellar ataxia type 7 patients

Expansion of polymorphic CAG repeats encoding polyglutamine cause at least eight inherited neurodegenerative diseases, including Huntington disease and the spinocerebellar ataxias. However, the pathways by which proteins containing expanded polyglutamine tracts cause disease remain unclear. To gain insight into the function of the SCA7 gene product, ataxin-7, as well as its contribution to cell death in spinocerebellar ataxia type 7 (SCA7), polyclonal antibodies were generated and ataxin-7 expression was examined within neuronal tissues from controls and three SCA7 patients. Immunoblotting demonstrates that ataxin-7 is widely expressed but that expression levels vary between tissues. Immunohistochemical analyses indicate that ataxin-7 is expressed within neurons both affected and unaffected in SCA7 pathology and that subcellular localization varies depending upon the neuronal subtype. Additionally, ataxin-7 staining was detected throughout control retina, including intense staining within the cell bodies and photosensitive outer segments of cone photoreceptors. Anti-ataxin-7 antibodies revealed intranuclear inclusions within surviving inferior olivary and cortical pyramidal neurons, as well as within surviving photoreceptor and ganglion cells of SCA7 patients harboring either 42 or 66 CAG repeats at the SCA7 locus. In contrast, inclusion formation was not detected within neurons of a patient with 41 repeats. This study broadens the current understanding of ataxin-7 localization and incorporates for the first time analysis of late-onset SCA7 patients where polyglutamine tract lengths are relatively shorter and disease course less severe than in previously described infantile-onset cases. Electronic Publication     

细胞凋亡在脊髓小脑性共济失调3型发病机制中的作用

目的研究细胞凋亡在脊髓小脑性共济失调3型(SCA3)分子发病机制中的作用。方法将带有SCA3正常与突变基因的增强型绿色荧光蛋白真核表达载体(pEGFP)转染大鼠肾上腺嗜铬细胞瘤(PC12)细胞,采用丫啶橙(AO)染色及电镜观察细胞凋亡的发生情况,免疫荧光检测转染后24h、72h、120h半胱氨酸天门冬氨酸酶3、8(caspase3、8)在细胞核内的分布及其与核内包涵体(INIs)共定位的情况;缺口末端标记(TUNEL)法观察正常基因组与突变基因组以及突变基因组在给予广谱caspase阻断剂zVAD-fmk(100μmol/L)后细胞凋亡的变化。结果随着转染后时间的延长,突变基因组细胞发生了明显的凋亡,caspase3、caspase8核内与INIs共定位。正常组与突变组TUNEL阳性细胞数有明显差异并有显著性意义(P<0.01),突变组在给予zVAD-fmk后细胞凋亡明显减轻,差异有显著性意义(P<0.01)。结论细胞凋亡在SCA3发病机制中起重要的作用,抑制凋亡通路可以减少细胞死亡,推测对凋亡环节的干预有可能成为SCA3治疗的靶点。     

脊髓小脑共济失调2型、3型患者10例基因突变与临床表型分析

目的探讨脊髓小脑共济失调（SCA）2型、3型患者的基因突变特点及临床表型。方法总结4个SCAs家系的9例患者和1例散发患者的临床表现，对全部患者、43名家系成员及60名健康对照，采用PCR、荧光PCR、毛细管电泳等技术检测分析SCA2、3基因内CAG三核苷酸重复序列的长度及拷贝数。结果3个家系中的6例患者、1例散发患者存在SCA3／MJD（CAG）n扩展突变，CAG重复数为68—75次；1个家系的3例患者存在SCA2（CAG）n扩展突变，CAG重复数为39—41次。两型患者的临床表现有重叠之处，但在发病年龄、病程进展、神经系统受累部位等方面有明显差异。结论SCA3／MJD型与SCA2型在临床表现上存在一定差异性，有助于鉴别和分型，但基因检测是明确诊断的惟一方法。     

Urine levels of the polyglutamine ataxin-3 protein are elevated in patients with spinocerebellar ataxia type 3

IntroductionAccumulation of polyglutamine (polyQ) ataxin-3 (ATXN3) contributes to the pathobiology of spinocerebellar ataxia type 3 (SCA3). Recently, we showed that polyQ ATXN3 is elevated in the plasma and cerebrospinal fluid (CSF) of SCA3 patients, and has the potential to serve as a biological marker for this disease [1]. Based on these findings, we investigated whether polyQ ATXN3 can also be detected in urine samples from SCA3 patients.MethodsWe analyzed urine samples from 30 SCA3 subjects (including one pre-symptomatic subject), 35 subjects with other forms of ataxia, and 37 healthy controls. To quantify polyQ ATXN3 protein levels, we used our previously developed immunoassay.ResultsPolyQ ATXN3 can be detected in the urine of SCA3 patients, but not in urine samples from healthy controls or other forms of ataxia. There was a significant statistical association between polyQ ATXN3 levels in urine samples and those in plasma. Further, the levels of polyQ ATXN3 urine associated with an earlier age of SCA3 disease onset.ConclusionAs clinical trials for SCA3 advance, urine polyQ ATXN3 protein has potential to be a useful, non-invasive and inexpensive biomarker for SCA3.     

Olfactory performance in spinocerebellar ataxia type 7 patients

A large body of evidence has shown olfactory deficits in many neurodegenerative diseases. However, the nature of the olfactory impairment remains poorly understood partly because the majority of studies have only explored smell identification capabilities. The purpose of the present study was twofold. First we wanted to test if patients with spinocerebellar ataxia type 7 (SCA7), a progressive neurodegenerative disorder characterized by cerebellar ataxia and visual loss, also have olfactory deficits. Secondly, we wanted to test the nature of the olfactory deficits by testing not only the identification level but also olfactory threshold and discrimination. Based on the olfactory dysfunction found in different neurodegenerative diseases and functional neuroimaging data showing cerebellar activation during olfaction, we hypothesized that SCA7 patients would show an olfactory impairment. To test this hypothesis we studied twenty-eight genetically confirmed SCA7 patients and twenty-seven matched controls using the Sniffing Sticks Test and the University of Pennsylvania Smell Identification Test (UPSIT). The results show that SCA7 patients' ability to discriminate and identify odors is significantly impaired, although their odor detection thresholds were at normal levels. These results suggest that SCA7 neurological damage affects olfactory perception but spares the patients' olfactory sensory capabilities.     

Inverse associations between cerebellar inhibition and motor impairment in spinocerebellar ataxia type 3

BackgroundCerebellar ataxia generally results from a lesion disrupting the corticopontocerebellar or cerebellothalamocortical tract. The cerebellar inhibition (CBI) paradigm represents a dual-coil transcranial magnetic stimulation protocol that interrogates the integrity of the latter pathway. Whether CBI has clinical relevance in ataxia patients remains largely unknown because associations with pertinent disease severity measures in etiologically homogeneous cohorts have not been previously examined.ObjectiveTo investigate if CBI correlates with clinical and functional indices of disease severity in individuals with spinocerebellar ataxia type 3 (SCA3).MethodsCBI was assessed in fourteen SCA3 patients by paired-pulse cerebellar-motor cortex (M1) stimulation using interstimulus intervals of 3, 5, and 10 ms. Correlation coefficients were determined between CBI and ataxia severity, manual dexterity, and walking speed.ResultsSuppression of M1 excitability occurred 5 ms following a contralateral cerebellar conditioning stimulus in SCA3 patients, but, on average, CBI was significantly reduced as compared to a healthy control group from the literature (p < 0.001). A significant association was found between decreased CBI levels and higher Scale for the Assessment and Rating of Ataxia (SARA) scores (r = −0.62, p = 0.019). CBI was negatively correlated with axial, appendicular, and speech subscores, as well as with nine-hole peg test performance (r = −0.69, p = 0.006). No association was observed between CBI and walking speed. As expected, there were no significant clinical-neurophysiological correlations at 3 and 10 ms interstimulus intervals.ConclusionOur results provide the first neurophysiological evidence for an inverse association between cerebellothalamocortical tract integrity, as reflected by reduced levels of CBI, and ataxia severity in SCA3 patients. Longitudinal studies are required to evaluate if CBI could serve as a marker of disease progression.     

两遗传性脊髓小脑型共济失调7型家系的临床特征和基因突变研究

目的 探讨遗传性脊髓小脑型共济失调(SCA)7型(SCA7)的临床特征和基因突变.方法 采用聚合酶链反应(PCR)和琼脂糖凝胶电泳(AGE)等技术,检测临床诊断为SCA的5个家系26例患者和37例表型正常的家系成员的SCA7基因内CAG三核苷酸重复次数,对异常等位基因片段进行DNA测序,分析临床表现和基因突变的关系. 结果 2个SCA7家系患者的SCA7等位基因内CAG重复数目为44～50次;临床表现主要为共济失调、视力下降及视网膜色素变性.该家系内表型正常的家系成员SCA7等位基因CAG重复数目为10～30. 结论 CAG过度扩增为SCA7的致病原因,分子遗传学分析有助于SCA7的诊断.     

Spinocerebellar ataxia type 3 presenting with writer's cramp without ataxia

Aim of the study: Spinocerebellar ataxia type 3 is the most common cause of autosomal dominant inherited ataxia worldwide.

Material and methods: Clinically, it exhibits wide phenotypic variability. Presentation as isolated dystonia is exceptional.

Results: Here, the case of a woman with writers cramp without ataxia is presented as a paucisymptomatic manifestation of this disease.

Conclusions: This association has not been described to date and extends the clinical variability of the disease.