The genetic locus of spinocerebellar ataxia type 3 (SCA3) is linked to chromosome 14q 24.3-qter like Machado-Joseph disease (MJD). The number of CAG repeats on mutant chromosome correlates positively with severity of disease, and negatively with the age of onset. However, the interindividual variation cannot be explained solely by the size of CAG repeats. We experienced a patient of juvenile onset SCA3, who had a relatively small length of CAG repeats. Several factors may have contributed in determining the age of on set in our case. The normal allele or modifying gene at other loci may have relationship with the age of onset and phenotype. Also, it should be considered that size of the expanded repeat in lymphocyte could be different from the size in cells of involved structures.
Age of Onset ; Alleles ; Genetic Loci ; Humans ; Lymphocytes ; Machado-Joseph Disease* ; Phenotype ; Spinocerebellar Ataxias* ; Trinucleotide Repeats

PURPOSE: Polyglutamine diseases are a group of diseases caused by the expansion of a polyglutamine tract in the protein. The present study was performed to verify if polyglutamine disease transgenic Drosophila models show similar dysfunctions as are seen in human patients. METHODS: Polyglutamine disease transgenic Drosophila were tested for their climbing ability. And using genetic methods, the effects of anti-apoptotic gene bcl-2 and chemical chaperones on neurodegeneration were observed. Also, spinocerebellar ataxia 2 (SCA2) transgenic Drosophila lines were generated for future studies. RESULTS: Expanded forms of spinocerebellar ataxia 3 (SCA3) transgenic protein causes characteristic locomotor dysfunction when expressed in the nervous system of Drosophila but the anti-apoptotic gene bcl-2 shows no evidence of ameliorating the deleterious effect of the expanded protein. However, Glycerol, a chemical chaperone, seemed to reduce the toxicity, at least in the eyes of the transgenic flies. The level SCA2 expression is too weak in the transgenic SCA2 Drosophila for evaluation. CONCLUSION: SCA3 transgenic Drosophila show ataxic behavior as observed in human patients. Chemical chaperones such as glycerol may prove beneficial in this class of genetic disease, which has no current method of cure.
Diptera ; Drosophila* ; Glycerol ; Humans ; Machado-Joseph Disease ; Nervous System ; Spinocerebellar Ataxias

OBJECTIVE: Machado-Joseph disease (MJD) is a spinocerebellar ataxia, and osteoporosis is a multifactor disease that may affect patients with neurologic conditions. The frequency of osteoporosis among MJD patients, however, has not been studied. The purpose of this study is to evaluate bone mineral density (BMD) and identify correlations between clinical factors and frequency of vertebral fractures in patients with MJD. METHODS: Clinical data, lumbar X-rays and BMD data were obtained in 30 patients with MJD. RESULTS: Ten patients (33.3%) showed low BMD in at least one of the sites studied based on Z-scores. The Z-score correlated directly with body mass index, and the femoral neck Z-score was inversely correlated with cytosine-adenine-guanine (CAG) expansion. There was no correlation between BMD and other clinical factors. Forty-three percent of the patients reported previous pathologic fractures. Five patients (16.7%) had at least one fracture detected by lumbar X-ray. CONCLUSION: Low BMD and fractures are frequent among MJD patients, and careful management of BMD may be beneficial for these patients.
Body Mass Index ; Bone Density ; Femur Neck ; Fractures, Spontaneous ; Humans ; Machado-Joseph Disease ; Osteoporosis ; Spinocerebellar Ataxias

OBJECTIVE: To determine the value of diffusion weighted imaging (DWI) in the diagnosis of hereditary spinocerebellar ataxia 3 and the Machado Joseph disease (SCA3/MJD) and hereditary spastic paraplegia 4 (SPG4). METHODS: We scanned 13 patients with SPG4, 30 patients with SCA3/MJD (21 onset patients and 9 with only genetic abnormalities), and 27 healthy volunteers with DWI. The processing data were apparent diffusion coefficient (ADC). The above data were grouped for comparative study. RESULTS: In the precentral gyrus, posterior limb of the internal capsule, cerebral peduncle, pons, cerebellar cortex and cerebellar white matter, the ADC of onset SCA3/MJD patients increased compared with the control group. The ADC of non-onset SCA3/MJD patients increased only in the cerebellar dentate nucleus compared with the control group. In the cerebellar cortex, the ADC of onset SCA3/MJD patients was significantly higher than the non-onset SCA3/MJD. The ADC of onset SCA3/MJD patients was significantly higher in the posterior limb of the internal capsule, cerebellar cortex, cerebellar white matter and pons than that of SPG4 patients. In the precentral gyrus, the ADC of SPG4 was significantly higher than control. CONCLUSION DWI is useful in the diagnosis of SCA3/MJD and SPG4.
Diffusion Magnetic Resonance Imaging ; Humans ; Machado-Joseph Disease ; diagnosis ; Paraplegia ; diagnosis ; Spastic Paraplegia, Hereditary ; diagnosis

OBJECTIVE: To analyze the dynamic variant and clinical subtype of a pedigree affected with spinocerebellar ataxia (SCA) by using fluorescent-labeled primer combined with capillary electrophoresis. METHODS: Genomic DNA was extracted from 8 members including 6 patients and 2 healthy individuals from the pedigree. Six pairs of fluorescent-labeled primers were designed to screen pathological variants in association with common subtypes of SCA including SCA1, SCA2, SCA3, SCA6, SCA12 and SCA17.The PCR products were detected by capillary electrophoresis. RESULTS: The number of CAG repeats in the SCA3 gene of the proband were determined as 8 and 70, exceeded the normal range(12 to 40), which suggested a diagnosis of SCA3. The other five patients were all detected with abnormal CAG repeats in the SCA3 gene, while the two healthy individuals were determined to be within the normal range. CONCLUSION The abnormal expansion of CAG repeats in the SCA3 gene probably underlay the pathogenesis of the disease in this pedigree. Combined fluorescent-labeled primers PCR and capillary electrophoresis can detect dynamic variants among SCA patients with efficiency and accuracy.
Ataxin-3/genetics* ; Genetic Variation ; Humans ; Machado-Joseph Disease/genetics* ; Pedigree ; Repressor Proteins/genetics* ; Trinucleotide Repeats/genetics*

OBJECTIVETo investigate the role of autophagy on the pathogenesis of spinocerebellar ataxia 3/Machado-Joseph disease (SCA3/MJD).

METHODSHEK293 cells expressing polyglutamine-expanded ataxin-3 were used as cell model for SCA3/MJD. The level of polyglutamine-expanded ataxin-3 was detected after cells were treated with different inhibitors or inducer of autophagy.

RESULTSInhibition of autophagy increased aggregate formation and cell death in HEK293 cells expressing mutated ataxin-3, and vice versa.

CONCLUSIONThe data suggested that autophagy is involved in the degradation of mutant ataxin-3, resulting in a decrease in the proportions of aggregate-containing cells and cell death in HEK293 cells expressing polyglutamine-expanded ataxin-3. It is possible that autophagy may be applied as a potential therapeutic approach for SCA3/MJD.

Ataxin-3 ; Autophagy ; Cell Line ; Humans ; Machado-Joseph Disease ; genetics ; metabolism ; physiopathology ; Mutation ; Nerve Tissue Proteins ; genetics ; metabolism ; Nuclear Proteins ; genetics ; metabolism ; Peptides ; metabolism ; Repressor Proteins ; genetics ; metabolism

BACKGROUNDSpinocerebellar ataxias (SCAs) are a group of neurodegenerative disorders that primarily cause the degeneration in the cerebellum, spinal cord, and brainstem. We study the clinical characteristics, radiological features and gene mutation in Chinese families with SCAs.

METHODSIn this study, we investigated 10 SCAs Chinese families with SCA1, SCA3/Machado-Joseph disease (MJD), SCA7, SCA8. There were 27 people who were genetically diagnosed as SCA, of which 21 people showed clinical symptoms, and 6 people had no clinical phenotype that we called them presymptomatic patients. In addition, 3 people with cerebellar ataxia and cataracts were diagnosed according to the Harding diagnostic criteria but failed to be recognized as SCAs on genetic testing. Clinical characteristic analyses of each type of SCAs and radiological examinations were performed.

RESULTSWe found that SCA3/MJD was the most common subtype in Han population in China, and the ratio of the pontine tegmentum and the posterior fossa area was negatively correlated with the number of cytosine-adenine-guanine (CAG) repeats; the disease duration was positively correlated with the International Cooperative Ataxia Rating Scale score; and the CAG repeats number of abnormal alleles was negatively correlated with the age of onset.

CONCLUSIONSCollectively our study is a systematic research on SCAs in China, which may help for the clinical diagnosis and prenatal screening of this disease, and it may also aid toward better understanding of this disease.

Adult ; DNA Repeat Expansion ; genetics ; Female ; Humans ; Machado-Joseph Disease ; genetics ; pathology ; Male ; Mutation ; genetics ; Spinocerebellar Ataxias ; genetics ; pathology ; Trinucleotide Repeat Expansion ; genetics

OBJECTIVEMachado-Joseph disease (MJD), also known as spinocerebellar ataxia type 3 (SCA3), is a dominant neurodegenerative disorder caused by an expansion of the polyglutamine (polyQ) tract in MJD-1 gene product, ataxin-3 (AT3). This disease is characterized by the formation of intraneuronal inclusions, but the mechanism underlying their formation is still poorly understood. The present study is to explore the relationship between wild type (WT) AT3 and polyQ expanded AT3.

METHODSMouse neuroblastoma (N2a) cells or HEK293 cells were co-transfected with WT AT3 and different truncated forms of expanded AT3. The expressions of WT AT3 and the truncated forms of expanded AT3 were detected by Western blotting, and observed by an inverted fluorescent microscope. The interactions between AT3 and different truncated forms of expanded AT3 were detected by immunoprecipitation and GST pull-down assays.

RESULTSUsing fluorescent microscope, we observed that the truncated forms of expanded AT3 aggregate in transfected cells, and the full-length WT AT3 is recruited onto the aggregates. However, no aggregates were observed in cells transfected with the truncated forms of WT AT3. Immunoprecipitation and GST pull-down analyses indicate that WT AT3 interacts with the truncated AT3 in a polyQ length-dependent manner.

CONCLUSIONWT AT3 deposits in the aggregation that was formed by polyQ expanded AT3, which suggests that the formation of AT3 aggregation may affect the normal function of WT AT3 and increase polyQ protein toxicity in MJD.

Animals ; Ataxin-3 ; Blotting, Western ; Cell Line ; Immunoprecipitation ; Machado-Joseph Disease ; metabolism ; Mice ; Microscopy, Fluorescence ; Nuclear Proteins ; genetics ; metabolism ; Peptides ; metabolism ; Transcription Factors ; genetics ; metabolism ; Transfection

BACKGROUNDSpinocerebellar ataxia type 3 (SCA3) is the most common subtype of SCA worldwide, and runs a slowly progressive and unremitting disease course. There is currently no curable treatment available. Growing evidence has suggested that nerve growth factor (NGF) may have therapeutic effects in neurodegenerative diseases, and possibly also in SCA3. The objective of this study was to test the efficacy of NGF in SCA3 patients.

METHODSWe performed an open-label prospective study in genetically confirmed adult (>18 years old) SCA3 patients. NGF was administered by intramuscular injection (18 μg once daily) for 28 days consecutively. All the patients were evaluated at baseline and 2 and 4 weeks after treatment using the Chinese version of the scale for assessment and rating of ataxia (SARA).

RESULTSTwenty-one SCA3 patients (10 men and 11 women, mean age 39.14 ± 7.81 years, mean disease duration 4.14 ± 1.90 years, mean CAG repeats number 77.57 ± 2.27) were enrolled. After 28 days of NGF treatment, the mean total SARA score decreased significantly from a baseline of 8.48 ± 2.40 to 6.30 ± 1.87 (P < 0.001). Subsections SARA scores also showed significant improvements in stance (P = 0.003), speech (P = 0.023), finger chase (P = 0.015), fast alternating hand movements (P = 0.009), and heel-shin slide (P = 0.001).

CONCLUSIONSOur preliminary data suggest that NGF may be effective in treating patients with SCA3.

Adult ; Animals ; Female ; Humans ; Injections, Intramuscular ; Machado-Joseph Disease ; drug therapy ; Male ; Mice ; Middle Aged ; Nerve Growth Factor ; administration & dosage ; therapeutic use ; Prospective Studies

To date, nearly 28 distinct genetic loci of autosomal dominant cerebellar ataxias have been identified, among them 18 disease-causing genes have been cloned. Of these, Machado-Joseph disease (MJD), also named as spinocerebellar ataxia type 3 (SCA3), is perhaps the most common subtype among different races and origins in the world. It is a neurodegenerative disease caused by the expansion of a CAG repeat in the coding region of the MJD1 gene, with obvious clinical and genetic heterogeneity. In this review, authors covered the recent advances in molecular genetic of SCA3/MJD.
Ataxin-3 ; Humans ; Machado-Joseph Disease ; genetics ; Molecular Biology ; Mutation ; Nerve Tissue Proteins ; chemistry ; genetics ; metabolism ; Nuclear Proteins ; chemistry ; genetics ; metabolism ; Repressor Proteins ; chemistry ; genetics ; metabolism