Dentatorubral-pallidoluysian Atrophy Research Articles

乳幼児期から精神運動発達遅滞を認めた若年型歯状核赤核淡蒼球ルイ体萎縮症(DRPLA)の1例

乳幼児期から精神運動発達遅滞を認めた若年型歯状核赤核淡蒼球ルイ体萎縮症(DRPLA)の1例

FAT10 Protein Binds to Polyglutamine Proteins and Modulates Their Solubility

Expansion of polyglutamine (pQ) chain by expanded CAG repeat causes dominantly inherited neurodegeneration such as Huntington disease, dentatorubral-pallidoluysian atrophy (DRPLA), and numbers of other spinocerebellar ataxias. Expanded pQ disrupts the stability of the pQ-harboring protein and increases its susceptibility to aggregation. Aggregated pQ protein is recognized by the ubiquitin proteasome system, and the enzyme ubiquitin ligase covalently attaches ubiquitin, which serves as a degradation signal by the proteasome. However, accumulation of the aggregated proteins in the diseased brain suggests insufficient degradation machinery. Ubiquitin has several functionally related proteins that are similarly attached to target proteins through its C terminus glycine residue. They are called ubiquitin-like molecules, and some of them are similarly related to the protein degradation pathway. One of the ubiquitin-like molecules, FAT10, is known to accelerate protein degradation through a ubiquitin-independent manner, but its role in pQ aggregate degradation is completely unknown. Thus we investigated its role in a Huntington disease cellular model and found that FAT10 molecules were covalently attached to huntingtin through their C terminus glycine. FAT10 binds preferably to huntingtin with a short pQ chain and completely aggregated huntingtin was FAT10-negative. In addition, ataxin-1,3 and DRPLA proteins were both positive for FAT10, and aggregation enhancement was observed upon FAT10 knockdown. These findings were similar to those for huntingtin. Our new finding will provide a new role for FAT10 in the pathogenesis of polyglutamine diseases.

Differential clinical features in a pair of monozygotic twins with dentatorubropallidoluysian atrophy

Differential clinical features in a pair of monozygotic twins with dentatorubropallidoluysian atrophy

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

To undertake an updated genetic spectrum analysis in patients with hereditary spinocerebellar ataxia (SCA) in mainland China. 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. 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. 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.

Clinical and genetic analysis of 29 Brazilian patients with Huntington's disease-like phenotype

Huntington's disease (HD) is a neurodegenerative disorder characterized by chorea, behavioral disturbances and dementia, caused by a pathological expansion of the CAG trinucleotide in the HTT gene. Several patients have been recognized with the typical HD phenotype without the expected mutation. The objective of this study was to assess the occurrence of diseases such as Huntington's disease-like 2 (HDL2), spinocerebellar ataxia (SCA) 1, SCA2, SCA3, SCA7, dentatorubral-pallidoluysian atrophy (DRPLA) and chorea-acanthocytosis (ChAc) among 29 Brazilian patients with a HD-like phenotype. In the group analyzed, we found 3 patients with HDL2 and 2 patients with ChAc. The diagnosis was not reached in 79.3% of the patients. HDL2 was the main cause of the HD-like phenotype in the group analyzed, and is attributable to the African ancestry of this population. However, the etiology of the disease remains undetermined in the majority of the HD negative patients with HD-like phenotype.

Autosomal dominant cerebellar ataxia type I: A review of the phenotypic and genotypic characteristics

Type I autosomal dominant cerebellar ataxia (ADCA) is a type of spinocerebellar ataxia (SCA) characterized by ataxia with other neurological signs, including oculomotor disturbances, cognitive deficits, pyramidal and extrapyramidal dysfunction, bulbar, spinal and peripheral nervous system involvement. The global prevalence of this disease is not known. The most common type I ADCA is SCA3 followed by SCA2, SCA1, and SCA8, in descending order. Founder effects no doubt contribute to the variable prevalence between populations. Onset is usually in adulthood but cases of presentation in childhood have been reported. Clinical features vary depending on the SCA subtype but by definition include ataxia associated with other neurological manifestations. The clinical spectrum ranges from pure cerebellar signs to constellations including spinal cord and peripheral nerve disease, cognitive impairment, cerebellar or supranuclear ophthalmologic signs, psychiatric problems, and seizures. Cerebellar ataxia can affect virtually any body part causing movement abnormalities. Gait, truncal, and limb ataxia are often the most obvious cerebellar findings though nystagmus, saccadic abnormalities, and dysarthria are usually associated. To date, 21 subtypes have been identified: SCA1-SCA4, SCA8, SCA10, SCA12-SCA14, SCA15/16, SCA17-SCA23, SCA25, SCA27, SCA28 and dentatorubral pallidoluysian atrophy (DRPLA). Type I ADCA can be further divided based on the proposed pathogenetic mechanism into 3 subclasses: subclass 1 includes type I ADCA caused by CAG repeat expansions such as SCA1-SCA3, SCA17, and DRPLA, subclass 2 includes trinucleotide repeat expansions that fall outside of the protein-coding regions of the disease gene including SCA8, SCA10 and SCA12. Subclass 3 contains disorders caused by specific gene deletions, missense mutation, and nonsense mutation and includes SCA13, SCA14, SCA15/16, SCA27 and SCA28. Diagnosis is based on clinical history, physical examination, genetic molecular testing, and exclusion of other diseases. Differential diagnosis is broad and includes secondary ataxias caused by drug or toxic effects, nutritional deficiencies, endocrinopathies, infections and post-infection states, structural abnormalities, paraneoplastic conditions and certain neurodegenerative disorders. Given the autosomal dominant pattern of inheritance, genetic counseling is essential and best performed in specialized genetic clinics. There are currently no known effective treatments to modify disease progression. Care is therefore supportive. Occupational and physical therapy for gait dysfunction and speech therapy for dysarthria is essential. Prognosis is variable depending on the type of ADCA and even among kindreds.

Analysis of the expression of normal and mutant full⁃length atrophin⁃1 gene in stable and transient transfected eukaryotic cell line

Objective To establish eukaryotic expression system of full ⁃ length gene in normal [CAG repeats (Q19)] and abnormal [CAG repeats (Q82 and Q66)] atrophin ⁃ 1 [the pathogenic gene of dentatorubral⁃pallidoluysian atrophy (DRPLA)]. To compare the expression system of stable and transient transfected cell line by observing the cellular appearance and atrophin⁃1 fusion protein expression and its distribution for further research on the establishment of a fine cell model. Methods Based on the 2 established stable transfected green⁃fluoresent protein (GFP)⁃atrophin⁃1⁃Q19/Flp⁃In TREx293 and GFP⁃ atrophin ⁃ 1 ⁃ Q82/Flp ⁃ In TREx293 cell lines, Tet ⁃ on system was used to induce the expression, which contained normal and abnormal atrophin ⁃ 1 full ⁃ length gene and GFP fusion proteins, respectively. Meanwhile, GFP ⁃ atrophin ⁃ 1 ⁃ Q19 and GFP ⁃ atrophin ⁃ 1 ⁃ Q66 recombinant plasmids were transiently transfected into 293T cells and SH⁃SY5Y cells respectively with LipofectamineTM 2000. The expression and localization of normal and abnormal atrophin ⁃ 1 fusion proteins in the cells were detected by light microscope with HE staining and fluorescence microscope; the ultrastructure of the cells were observed by electron microscope; the expression of GFP ⁃ atrophin ⁃ 1 fusion proteins were detected by Western blotting. Results In stable transfected system, the green fluorescence signals were detected in the nucleus, and abnormal proteins were not uniformly distributed while some were aggregated. Electron microscope showed shrinkaged nuclear membrane and abnormal intranuclear structure in abnormal cells. In transient transfection of 293T, Q66 protein aggregated in the nucleus which was detected as acidophilic bodies by HE staining⁃light microscope and atrophin⁃1 fusion protein as punctuate pattern by fluorescence microscope. Under the observation of electron microscope, great quantity of electron ⁃ dense substance accumulation, distinct shrinkage nuclear membrane and nucleus disappearance were seen in abnormal cells. The expression of GFP ⁃ atrophin ⁃ 1 fusion proteins were detected by Western blotting. The location of protein expression and Western blotting results in transient transfected SH⁃SY5Y cells system were essentially similar to those in transfected 293T cells. Conclusion In eukaryotic cell expression system, atrophin⁃1 with amplified polyglutamine chain may induce obvious aberrant aggregation in nucleus, and alteration of cellular appearance. The establishment of atrophin⁃1 expression eukaryotic cell model will provide the foundation for the research of pathogenesis of DRPLA, and therotic basis for further investigation of clincial intervention. DOI：10.3969/j.issn.1672-6731.2011.01.016

Polyglutamine Atrophin provokes neurodegeneration inDrosophilaby repressingfat

Large alterations in transcription accompany neurodegeneration in polyglutamine (polyQ) diseases. These pathologies manifest both general polyQ toxicity and mutant protein-specific effects. In this study, we report that the fat tumour suppressor gene mediates neurodegeneration induced by the polyQ protein Atrophin. We have monitored early transcriptional alterations in a Drosophila model of Dentatorubral-pallidoluysian Atrophy and found that polyQ Atrophins downregulate fat. Fat protects from neurodegeneration and Atrophin toxicity through the Hippo kinase cascade. Fat/Hippo signalling does not provoke neurodegeneration by stimulating overgrowth; rather, it alters the autophagic flux in photoreceptor neurons, thereby affecting cell homeostasis. Our data thus provide a crucial insight into the specific mechanism of a polyQ disease and reveal an unexpected neuroprotective role of the Fat/Hippo pathway.

Clinical and genetic study of one DRPLA case

Objective To investigate the clinical and genetic features of dentatorubral ⁃ pallidoluysian atrophy (DRPLA). Methods The trinucleotide repeats of spinocerebellar ataxia (SCA) disease genes were detected by polymerase chain reaction (PCR) initially in 388 SCA cases which included 234 cases with autosomal dominant inheritance and 154 sporadic cases. Fragment analysis with laser ⁃ induced fluorescence in capillary electrophoresis was performed for the samples with 2 bands detected by agarose gel electrophoresis (AGE). The repeat numbers of the positive or suspicious samples were verified by the pUC18⁃T vector cloning and sequencing. Results Based on the 2 methods, the cytosine⁃adenine⁃ guanine (CAG) repeat expansion of DRPLA gene was detected in one female case with mild ataxia and suspected seizure. The repeat numbers of the 2 alleles were 14 and 54 by fragment analysis, and 15 and 58 by cloning sequencing. The 2 members of her family had a history of seizure, but no obvious ataxia. The CAG repeat numbers of the other 19 cases without abnormal expansions ranged from 7 to 20, of which 9 was common. Conclusion The patient's atypical manifestations suggests that clinical variation may exist in DRPLA. Only one case of DRPLA is found in 388 SCA cases, indicating that DRPLA may be a relatively rare subtype of SCA in Chinese population. The secondary structure of DNA owing to the highly repetitive sequences will induce DNA polymerase sliding during the amplification, which will reduce the fidelity in DNA replication. This problem exists in both fragment analysis and cloning sequencing. For the latter method, the instability also appears in the process of cloning. Therefore, the repeat numbers need to be mutually verified by the 2 methods. DOI：10.3969/j.issn.1672-6731.2010.06.012

SCA31 is rare in the Chinese population on Taiwan

Spinocerebellar ataxia (SCA) is a clinically, pathologically, and genetically heterogeneous group of dominantly inherited neurodegenerative disorders. SCA31 has recently been reported to be associated with a complex penta-nucleotide (TGGAA)n repeat insertion in the introns of TK2 and BEAN. In this study we excluded SCA31 mutation from 119 unrelated patients with molecularly unassigned hereditary cerebellar ataxia, out of 512 pedigrees, after mutations in SCA1, 2, 3, 6, 7, 8, 10, 12, 17, and dentatorubral-pallidoluysian atrophy (DRPLA) had been excluded. Our data indicate that SCA31 is absent or rare in the Chinese population on Taiwan.

Spinocerebellar ataxia type 17 in Indian patients: two rare cases of homozygous expansions

We screened a cohort of 181 patients with features of primary progressive ataxia and chorea for spinocerebellar ataxias 17 (SCA17) mutation after excluding other known SCAs, Huntington's disease (HD), dentatorubral-pallidoluysian atrophy (DRPLA), and non-genetic causes. This study included patients with known family history of SCA, those with sporadic onset and cases of uncertain family history. Two unrelated patients with Huntington's disease-like phenotype and cerebellar signs are described with homozygous expansions of 47 and 48 CAG/CAA repeats. A family member with early signs of ataxia was found to carry 37 and 48 repeats. There were fewer CAA interruptions in the repeat sequences of patients than in the controls. The normal repeat range in controls was 21-42, with 91% of the alleles located between 33 and 39 repeats. This is the first report of rare homozygous SCA17 mutation in Indian patients presenting with HD-like phenotype.

An Interdomain Interaction of the Androgen Receptor Is Required for Its Aggregation and Toxicity in Spinal and Bulbar Muscular Atrophy

Polyglutamine expansion within the androgen receptor (AR) causes spinal and bulbar muscular atrophy (SBMA) and is associated with misfolded and aggregated species of the mutant AR. We showed previously that nuclear localization of the mutant AR was necessary but not sufficient for SBMA. Here we show that an interdomain interaction of the AR that is central to its function within the nucleus is required for AR aggregation and toxicity. Ligands that prevent the interaction between the amino-terminal FXXLF motif and carboxyl-terminal AF-2 domain (N/C interaction) prevented toxicity and AR aggregation in an SBMA cell model and rescued primary SBMA motor neurons from 5α-dihydrotestosterone-induced toxicity. Moreover, genetic mutation of the FXXLF motif prevented AR aggregation and 5α-dihydrotestosterone toxicity. Finally, selective androgen receptor modulators, which prevent the N/C interaction, ameliorated AR aggregation and toxicity while maintaining AR function, highlighting a novel therapeutic strategy to prevent the SBMA phenotype while retaining AR transcriptional function.

Proteolytic processing regulates pathological accumulation in dentatorubral‐pallidoluysian atrophy

Dentatorubral-pallidoluysian atrophy is caused by polyglutamine (polyQ) expansion in atrophin-1 (ATN1). Recent studies have shown that nuclear accumulation of ATN1 and cleaved fragments with expanded polyQ is the pathological process underlying neurodegeneration in dentatorubral-pallidoluysian atrophy. However, the mechanism underlying the proteolytic processing of ATN1 remains unclear. In the present study, we examined the proteolytic processing of ATN1 aiming to understand the mechanisms of ATN1 accumulation with polyQ expansion. Using COS-7 and Neuro2a cells that express the ATN1 gene, in which ATN1 was accumulated by increasing the number of polyQs, we identified a novel C-terminal fragment containing a polyQ tract. The mutant C-terminal fragment with expanded polyQ selectively accumulated in the cells, and this was also demonstrated in the brain tissues of patients with dentatorubral-pallidoluysian atrophy. Immunocytochemical and biochemical studies revealed that full-length ATN1 and C-terminal fragments displayed individual localization. The mutant C-terminal fragment was preferentially found in the cytoplasmic membrane/organelle and insoluble fractions. Accordingly, it is assumed that the proteolytic processing of ATN1 regulates the localization of C-terminal fragments. Accumulation of the C-terminal fragment was enhanced by inhibition of caspases in the cytoplasm of COS-7 cells. Collectively, these results suggest that the C-terminal fragment plays a principal role in the pathological accumulation of ATN1 in dentatorubral-pallidoluysian atrophy.

Radiologic and Neuropathologic Findings in Patients in a Family with Dentatorubral-Pallidoluysian Atrophy

We describe the cases of 2 patients, a father and his son, with DRPLA who underwent MR examinations prior to death and in whom postmortem examinations of the brain were obtained. MR imaging findings had the following features: 1) atrophy of the cerebellum and brain stem were the common findings, 2) high-signal-intensity lesions in the cerebral white matter and brain stem were observed on T2-weighted images in the patient with adult-onset DRPLA, 3) signal-intensity changes in the cerebral white matter were restricted to the periventricular white matter in the patient with juvenile-onset DRPLA, but these changes appear in the advanced stage, and 4) progressive cerebral atrophy was more marked in the patient with juvenile-onset DRPLA. In the patients with DRPLA, the abnormal high signal intensity of the cerebral white matter or brain stem on MR images reflect the loss of myelinated fibers. Cerebral atrophy mainly reflects atrophy of the neuropile.

Polynucleotide repeat expansion of nine spinocerebellar ataxia subtypes and dentatorubral-pallidoluysian atrophy in healthy Chinese Han population

To assist the establishment of platform and provide the reference standard for mutation detection in spinocerebellar ataxia (SCA) subtypes 1, 2, 3, 6, 7, 8, 10, 12, 17 and dentatorubral-pallidoluysian atrophy (DRPLA) in Chinese Han population. The nucleotide repeat numbers of the 9 SCA subtypes and DRPLA were detected using fluorescence-PCR and capillary gel electrophoresis technique in 300 healthy Chinese Han individuals. Among the 300 healthy controls, the range of the CAG trinucleotide repeat number was 17 to 35 in SCA1, 14-28 in SCA2, 13-41 in SCA3/MJD, 4-16 in SCA6, 5-17 in SCA7, 5-21 in SCA12, 23-41 in SCA17, and 12-33 in DRPLA; and the range of CTA/CTG trinucleotide repeat number on SCA8 locus was 12-43 and the range of ATTCT pentanucleotide repeat number on SCA10 locus was 9-32. Of which, the 12 CTA/CTG repeats of SCA8, 9 ATTCT repeats of SCA10, 23 CAG repeats of SCA17 were the shortest normal repeat number, while the 41 CAG repeats of SCA3/MJD, 32 CAG repeats of SCA10 were the largest normal number that have not been reported. The normal ranges of polynucleotide repeats of different subtypes of SCA vary with geographical areas and ethnicities. It might be associated with the genetic and ethnic backgrounds. This is the first normal reference standard of polynucleotide repeat number of these ten SCA subtypes in Chinese Han.

B09 One antisense oligonucleotide as a potential therapy for polyglutamine disorders

BackgroundTo date there are nine known polyglutamine (polyQ) disorders: spinal bulbar muscular atrophy (SBMA), dentatorubral-pallidoluysian atrophy (DRPLA), Huntington's disease (HD) and spinocerebellar ataxias (SCA1, 2, 3, 6, 7, and 17)....

Long‐term disability and prognosis in dentatorubral‐pallidoluysian atrophy: A correlation with CAG repeat length

Dentatorubral-pallidoluysian atrophy (DRPLA) is a rare autosomal dominant neurodegenerative disorder caused by CAG repeat expansion. Previous studies demonstrated that the onset of DRPLA is closely associated with CAG repeat length. However, the natural history of DRPLA has not yet been evaluated. We here retrospectively investigated the factors that determine the disease milestones and prognosis in 183 Japanese patients genetically diagnosed with DRPLA. We determined the age at onset, age at which each of the subsequent clinical manifestations appeared, age at becoming wheelchair-bound, and age at death. Kaplan-Meier analysis revealed that the patients with CAG repeats larger than the median length of 65 repeats developed each of the clinical features of DRPLA at a younger age than those with <65 repeats. The patients became wheelchair-bound at a median age of 33 years (n = 61; range, 3-77 years) and died at a median age of 49 years (n = 23; range, 18-80 years). The ages at becoming wheelchair-bound and at death strongly correlated with the expanded CAG repeat length. Moreover, the patients with >or=65 CAG repeats showed a more severe long-term disability and a poorer prognosis. In contrast, the rate of progression after the onset did not correlate with CAG repeat length. The CAG repeat length may have a considerable effect on not only the disease onset but also the disease milestones and prognosis in DRPLA patients. These effects of CAG repeat length may be relevant in designing future clinical therapeutic trials.

Dentatorubral pallidoluysian atrophy presenting with urinary retention

Dentatorubral pallidoluysian atrophy presenting with urinary retention

Molecular genetic analysis of a new form of spinocerebellar ataxia in a Chinese Han family

The pathological changes of spinocerebellar ataxias (SCAs), mainly include the degeneration of the cerebellum, spinal cord and brainstem. To investigate the genotype of a three-generation Chinese Han pedigree with an autosomal dominant SCA for clinical diagnosis and genetic counseling, direct mutation test and linkage analysis were performed. SCA1–8, SCA10–14, SCA17, SCA27 and dentatorubral-pallidoluysian atrophy (DRPLA) were excluded by mutation analysis while SCA15/16/29, SCA18, SCA19/22, SCA20, SCA21, SCA23, SCA25, SCA26, SCA28 and SCA30 were excluded by linkage analysis. Therefore, we excluded all of the previously identified SCA-associated genes and loci. Interestingly, one patient (III-13) had a novel mutation of the pleckstrin homology domain containing, family G (with RhoGef domain) member 4 gene (PLEKHG4), and another patient (II-7) had a novel mutation of the β-III spectrin gene (SPTBN2) (Genbank accession numbers FJ905766 and FJ811850, respectively). However, mutations of the PLEKHG4 gene and the SPTBN2 gene are not the causes of SCAs in this family. We conclude that this autosomal dominant cerebellar ataxia family is likely a new genotype of SCAs.

Dentatorubropallidoluysian atrophy without involuntary movement or dementia—A case report

Recently, discussions about the clinical features of dentatorubropallidoluysian atrophy (DRPLA), especially the existence of an ataxo-choreoathetoid type, have increased. Traditionally, DRPLA patients have been thought to present with involuntary movements and dementia. Here, we report a patient that presented with ataxia, spasticity of the right lower extremity and mild sensory disturbances. He did not show either apparent involuntary movement or dementia. Mini-mental state examination demonstrated a score of 29/30. The cerebellar output system involving the dentate nuclei and superior cerebellar peduncles seemed to be atrophic yet the cerebellar input system involving the middle cerebellar peduncles was preserved on MRI. In addition, there was an expansion of the atrophin1 (ATN1) CAG repeat of chromosome 12p: 9/61. This seems to be the first case report of a genetically confirmed DRPLA patient presenting with clinical manifestations of Machado-Joseph disease (MJD/SCA3).