RESUMO
OBJECTIVE: To analyze clinical and genetic characteristics of patients with the verified rare forms of autosomal recessive spinocerebellar ataxias, ATX-ANO10 and ATX-SYNE1. MATERIAL AND METHODS: Six unrelated patients with established diagnoses were examined: 4 patients with ATX-ANO10 and 2 patients with ATX-SYNE1. Brain MRI and nerve conduction study were performed. To screen for cognitive impairment, the scale for the Assessment and Rating of Ataxia (SARA), and the Montreal Cognitive Assessment Scale (MoCA) were used. Mutation screening included panel sequencing on the Illumina MiSeq platform. RESULTS: Six variants were found in the ANO10 gene: the previously described pathogenic nonsense mutations c.G1025A (p.W342X) and c.C1244G (p.S415X), as well as novel probably pathogenic variants c.1477-2A>G and c.G101T (p.W34L) and missense mutations c.A110C (p.N37T) and c.T104C (p.L35P) of undetermined significance. A novel nonsense mutation c.C8911T (p.Q2971X) and a previously described pathogenic variant c.C4939T (p.Q1647X) were found in the SYNE1 gene. The clinical presentation of the ATX-ANO10 and ATX-SYNE1 was typical presenting with slowly progressive cerebellar ataxia with pyramidal signs, with young onset and cerebellar atrophy according to brain MRI study. CONCLUSION: We provided first-ever data on clinical features and mutation spectrum In Russian patients with ATX-ANO10 and ATX-SYNE1. The phenotype of these ataxias is nonspecific, so the method of choice for molecular diagnostics is massive parallel sequencing.
Assuntos
Anoctaminas , Proteínas do Citoesqueleto , Proteínas do Tecido Nervoso , Ataxias Espinocerebelares , Humanos , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/diagnóstico por imagem , Masculino , Feminino , Proteínas do Tecido Nervoso/genética , Adulto , Proteínas do Citoesqueleto/genética , Anoctaminas/genética , Mutação , Proteínas Nucleares/genética , Pessoa de Meia-Idade , Imageamento por Ressonância Magnética , Códon sem Sentido , Mutação de Sentido Incorreto , Adolescente , Adulto JovemRESUMO
BACKGROUND: Spinocerebellar ataxia type 1, is a rare neurodegenerative disorder with autosomal dominant inheritance belonging to the polyglutamine diseases. The diagnosis of this disease requires genetic testing that may also include the search for CAT interruption of the CAG repeat tract. CASE PRESENTATION: One 23-years-old patient suffers from a severe ataxia, with early-onset and rapid progression of the disease. His father might have been affected, but no molecular confirmation has been performed. The genetic results were negative for the Friedreich's ataxia, spinocerebellar ataxia type 2, 3, 6, 7 and 17. The numbers of CAG repeats in the ATXN1 gene was assessed by fluorescent PCR, tripled-primed PCR and enzymatic digestion for the search of sequence interruption in the CAG repeats. The patient carried one pathogenic allele of 61 CAG and one intermediate allele of 37 CAG in the ATXN1 gene. Both alleles were uninterrupted. CONCLUSIONS: We report a rare case of spinocerebellar ataxia type 1 with an intermediate allele and a large SCA1 expansion. The determination of the absence of CAT interruption brought crucial information concerning this molecular diagnosis, the prediction of the disease and had practical consequences for genetic counseling.
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Ataxina-1 , Fenótipo , Ataxias Espinocerebelares , Humanos , Masculino , Ataxina-1/genética , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/diagnóstico , Adulto Jovem , Alelos , Idade de Início , Expansão das Repetições de Trinucleotídeos/genética , Proteínas do Tecido Nervoso/genética , Ataxinas/genéticaAssuntos
Microglia , Espasticidade Muscular , Ataxias Espinocerebelares , Humanos , Microglia/patologia , Microglia/metabolismo , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/patologia , Ataxias Espinocerebelares/congênito , Espasticidade Muscular/genética , Espasticidade Muscular/patologiaRESUMO
Since 1991, several genetic disorders caused by unstable trinucleotide repeats (TNRs) have been identified, collectively referred to as triplet repeat diseases (TREDs). They share a common mutation mechanism: the expansion of repeats (dynamic mutations) due to the propensity of repeated sequences to form unusual DNA structures during replication. TREDs are characterized as neurodegenerative diseases or complex syndromes with significant neurological components. Spinocerebellar ataxia type 17 (SCA17) falls into the former category and is caused by the expansion of mixed CAA/CAG repeats in the TBP gene. To date, a five-unit organization of this region [(CAG)3 (CAA)3] [(CAG)n] [CAA CAG CAA] [(CAG)n] [CAA CAG], with expansion in the second [(CAG)n] unit being the most common, has been proposed. In this study, we propose an alternative organization scheme for the repeats. A search of the PubMed database was conducted to identify articles reporting both the number and composition of GAC/CAA repeats in TBP alleles. Nineteen reports were selected. The sequences of all identified CAG/CAA repeats in the TBP locus, including 67 cases (probands and b relatives), were analyzed in terms of their repetition structure and stability in inheritance, if possible. Based on the analysis of three units [(CAG)3 (CAA)2] [CAA (CAG)n CAA CAG] [CAA (CAG)n CAA CAG], the organization of repeats is proposed. Detailed analysis of the CAG/CAA repeat structure, not just the number of repeats, in TBP-expanded alleles should be performed, as it may have a prognostic value in the prediction of stability/instability during transmission and the possible anticipation of the disease.
Assuntos
Mutação , Proteína de Ligação a TATA-Box , Expansão das Repetições de Trinucleotídeos , Humanos , Alelos , Ataxias Espinocerebelares/genética , Degenerações Espinocerebelares/genética , Proteína de Ligação a TATA-Box/genética , Expansão das Repetições de Trinucleotídeos/genética , Repetições de Trinucleotídeos/genéticaRESUMO
Spinocerebellar ataxias (SCAs) are a genetically heterogeneous group of autosomal dominant movement disorders. Among the SCAs associated with impaired ion channel function, SCA19/22 is caused by pathogenic variants in KCND3, which encodes the voltage-gated potassium channel Kv4.3. SCA19/22 is clinically characterized by ataxia, dysarthria and oculomotor dysfunction in combination with other signs and symptoms, including mild cognitive impairment, peripheral neuropathy and pyramidal signs. The known KCND3 pathogenic variants are localized either in the transmembrane segments, the connecting loops, or the C-terminal region of Kv4.3. We have identified a novel pathogenic variant, c.455A>G (p.D152G), localized in the N-terminus of Kv4.3. It is located in the immediate neighbourhood of the T1 domain, which is responsible for multimerization with the ß-subunit KChIP2b and thus for the formation of functional heterooctamers. Electrophysiological studies showed that p.D152G does not affect channel gating, but reduces the ionic current in Kv4.3, even though the variant is not located in the transmembrane domains. Impaired channel trafficking to the plasma membrane may contribute to this effect. In a patient with a clinical picture corresponding to SCA19/22, p.D152G is the first pathogenic variant in the N-terminus of Kv4.3 to be described to date with an effect on ion channel activity.
Assuntos
Canais de Potássio Shal , Ataxias Espinocerebelares , Humanos , Canais de Potássio Shal/genética , Canais de Potássio Shal/metabolismo , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/metabolismo , Ataxias Espinocerebelares/patologia , Masculino , Feminino , Animais , Ativação do Canal Iônico , Células HEK293 , Proteínas Interatuantes com Canais de Kv/metabolismo , Proteínas Interatuantes com Canais de Kv/genética , Pessoa de Meia-Idade , Mutação/genética , Degenerações EspinocerebelaresRESUMO
BACKGROUND AND OBJECTIVES: Brain MRI abnormalities and increases in neurofilament light chain (NfL) have mostly been observed in cross-sectional studies before ataxia onset in polyglutamine spinocerebellar ataxias. Our study aimed to identify longitudinal changes in biological, clinical, and/or imaging biomarkers in spinocerebellar ataxia (SCA) 2 and SCA7 carriers over 1 year. METHODS: We studied SCA2 and SCA7 carriers and controls (expansion-negative relatives) at the Paris Brain Institute. Inclusion criteria included Scale for the Assessment and Rating of Ataxia (SARA) scores between 0 and 15. Assessments at baseline, 6 months, and 12 months comprised neurologic, quality of life, orofacial motor, neuropsychological, and ophthalmologic examinations, along with gait and oculomotor recordings, brain MRI, CSF, and blood sampling. The primary outcome was the longitudinal change in these assessments over 1 year. RESULTS: We included 15 SCA2 carriers, 15 SCA7 carriers, and 10 controls between May 2020 and April 2021. At baseline, the ages were similar (41 [37, 46] for SCA2, 38 [28.5, 39.8] for SCA7, and 39.5 [31, 54.5] for controls, p = 0.78), as well the sex (p = 0.61); SARA scores were low but different (4 [1.25, 6.5] in SCA2, 2 [0, 11.5] in SCA7, and 0 in controls, p < 0.01). Pons and medulla volumes were smaller in SCAs (p < 0.05) and cerebellum volume only in SCA2 (p = 0.01). Plasma NfL levels were higher in SCA participants (SCA2: 14.2 pg/mL [11.52, 15.89], SCA7: 15.53 [13.27, 23.23]) than in controls (4.88 [3.56, 6.17], p < 0.001). After 1-year follow-up, in SCA2, there was significant pons (-144 ± 60 mm3) and cerebellum (-1,508 ± 580 mm3) volume loss and a worsening of gait assessment; in SCA7, SARA score significantly increased (+1.3 ± 0.4) and outer retinal nuclear layer thickness decreased (-15.4 ± 1.6 µm); for both SCA groups, the orofacial motor assessment significantly worsened. For preataxic and early ataxic carriers, the strongest longitudinal deterioration on outcome measures was orofacial motility in SCA2 and retinal thickness in SCA7. DISCUSSION: Despite the limitation of the small sample size, we detected annual changes in preataxic and early ataxic SCA individuals across brain MRI imaging, clinical scores, gait parameters, and retinal thickness. These parameters could serve as potential end points for future therapeutic trials in the preataxic phase. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov NCT04288128.
Assuntos
Biomarcadores , Imageamento por Ressonância Magnética , Proteínas de Neurofilamentos , Ataxias Espinocerebelares , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Ataxias Espinocerebelares/diagnóstico por imagem , Ataxias Espinocerebelares/genética , Adulto , Biomarcadores/sangue , Estudos Longitudinais , Proteínas de Neurofilamentos/sangue , Heterozigoto , Ataxina-7/genética , Ataxina-2/genética , Progressão da Doença , Encéfalo/diagnóstico por imagemRESUMO
BACKGROUND: Recently, an exonic GGC repeat expansion (RE) was identified by long-read genome sequencing in the ZFHX3 gen, causing spinocerebellar ataxia type 4 (SCA4), a dominant form of ataxia with sensory neuropathy. However, the analysis of larger cohorts of patients remained demanding, resulting in a challenge to diagnose patients and leaving the question of anticipation in SCA4 unanswered. OBJECTIVES: We aimed to develop a GGC repeat test for clinical SCA4 screening and to apply this test to screen two large German SCA pedigrees and samples of unrelated patients collected over the last 25 years. METHODS: We modulated a commercial GGC-RE kit (Bio-Techne AmplideX® Asuragen® PCR/CE FMR1 Reagents) with ZFHX3-specific primers and adapted PCR conditions. The test was applied to patients and 50 healthy controls to determine the exact repeat number. Clinical data were revised and correlated with the expanded allele sizes and an exploratory analysis of structural MRI was performed. RESULTS: Repeat size, determined by our protocol for (GGC)n RE analysis shows a strong inverse correlation between repeat length and age at onset and anticipation in subsequent generations. The phenotype also appears to be more strongly expressed in carriers of longer RE. Clinical red flags were slowed saccades, sensory neuropathy and autonomic dysfunction. CONCLUSION: Our protocol enables cost-effective and robust screening for the causative SCA4 RE within ZFHX3. Furthermore, detailed clinical data of our patients gives a more precise view on SCA4, which seems to be more common among patients with ataxia than expected.
Assuntos
Idade de Início , Índice de Gravidade de Doença , Ataxias Espinocerebelares , Humanos , Masculino , Feminino , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/diagnóstico , Ataxias Espinocerebelares/diagnóstico por imagem , Ataxias Espinocerebelares/fisiopatologia , Pessoa de Meia-Idade , Adulto , Expansão das Repetições de Trinucleotídeos/genética , Linhagem , IdosoRESUMO
Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant neurological disorder caused by deleterious CAG repeat expansion in the coding region of the ataxin 7 gene (polyQ-ataxin-7). Infantile-onset SCA7 leads to severe clinical manifestation of respiratory distress, but the exact cause of respiratory impairment remains unclear. Using the infantile-SCA7 mouse model, the SCA7266Q/5Q mouse, we examined the impact of pathological polyQ-ataxin-7 on hypoglossal (XII) and phrenic motor units. We identified the transcript profile of the medulla and cervical spinal cord and investigated the XII and phrenic nerves and the neuromuscular junctions in the diaphragm and tongue. SCA7266Q/5Q astrocytes showed significant intranuclear inclusions of ataxin-7 in the XII and putative phrenic motor nuclei. Transcriptomic analysis revealed dysregulation of genes involved in amino acid and neurotransmitter transport and myelination. Additionally, SCA7266Q/5Q mice demonstrated blunted efferent output of the XII nerve and demyelination in both XII and phrenic nerves. Finally, there was an increased number of neuromuscular junction clusters with higher expression of synaptic markers in SCA7266Q/5Q mice compared with WT controls. These preclinical findings elucidate the underlying pathophysiology responsible for impaired glial cell function and death leading to dysphagia, aspiration, and respiratory failure in infantile SCA7.
Assuntos
Modelos Animais de Doenças , Nervo Hipoglosso , Nervo Frênico , Ataxias Espinocerebelares , Animais , Camundongos , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/patologia , Nervo Hipoglosso/patologia , Nervo Frênico/patologia , Ataxina-7 , Bulbo/patologia , Bulbo/metabolismo , Junção Neuromuscular/patologia , Junção Neuromuscular/metabolismo , Camundongos Transgênicos , Humanos , Masculino , Feminino , Diafragma/patologia , Diafragma/fisiopatologia , Astrócitos/patologia , Astrócitos/metabolismo , Língua/patologia , Medula Espinal/patologia , Medula Espinal/metabolismo , PeptídeosRESUMO
PURPOSE: Spinocerebellar ataxia SCA1 and SCA2 are adult-onset hereditary disorders, due to triplet CAG expansion in their respective causative genes. The pathophysiology of SCA1 and SCA2 suggests alterations of cerebello-thalamo-cortical pathway and its connections to the basal ganglia. In this framework, thalamic integrity is crucial for shaping efficient whole-brain dynamics and functions. The aims of the study are to identify structural changes in thalamic nuclei in presymptomatic and symptomatic SCA1 and SCA2 patients and to assess disease progression within a 1-year interval. MATERIAL AND METHODS: A prospective 1-year clinical and MRI assessment was conducted in 27 presymptomatic and 23 clinically manifest mutation carriers for SCA1 and SCA2 expansions. Cross-sectional and longitudinal changes of thalamic nuclei volume were investigated in SCA1 and SCA2 individuals and in healthy participants (n = 20). RESULTS: Both SCA1 and SCA2 patients had significant atrophy in the majority of thalamic nuclei, except for the posterior and partly medial nuclei. The 1-year longitudinal evaluation showed a specific pattern of atrophy in ventral and posterior thalamus, detectable even at the presymptomatic stage of the disease. CONCLUSION: For the first time in vivo, our exploratory study has shown that different thalamic nuclei are involved at different stages of the degenerative process in both SCA1 and SCA2. It is therefore possible that thalamic alterations might significantly contribute to the progression of the disease years before overt clinical manifestations occur.
Assuntos
Progressão da Doença , Imageamento por Ressonância Magnética , Ataxias Espinocerebelares , Tálamo , Humanos , Masculino , Feminino , Ataxias Espinocerebelares/diagnóstico por imagem , Ataxias Espinocerebelares/patologia , Ataxias Espinocerebelares/genética , Adulto , Estudos Prospectivos , Pessoa de Meia-Idade , Imageamento por Ressonância Magnética/métodos , Tálamo/diagnóstico por imagem , Tálamo/patologia , Estudos Transversais , Atrofia/diagnóstico por imagem , Ataxina-1/genética , Estudos Longitudinais , Ataxina-2/genética , Tamanho do ÓrgãoRESUMO
Background: For various genetic disorders characterized by expanded cytosine-adenine-guanine (CAG) repeats, such as spinocerebellar ataxia (SCA) subtypes and Huntington's disease (HD), genetic interventions are currently being tested in different clinical trial phases. The patient's perspective on such interventions should be included in the further development and implementation of these new treatments. Objective: To obtain insight into the thoughts and perspectives of individuals with SCA and HD on genetic interventions. Methods: In this qualitative study, participants were interviewed using semi-structured interview techniques. Topics discussed were possible risks and benefits, and logistic factors such as timing, location and expertise. Data were analyzed using a generic thematic analysis. Responses were coded into superordinate themes. Results: Ten participants (five with SCA and five with HD) were interviewed. In general, participants seemed to be willing to undergo genetic interventions. Important motives were the lack of alternative disease-modifying treatment options, the hope for slowing down disease progression, and preservation of current quality of life. Before undergoing genetic interventions, participants wished to be further informed. Logistic factors such as mode and frequency of administration, expertise of the healthcare provider, and timing of treatment are of influence in the decision-making process. Conclusions: This study identified assumptions, motives, and topics that require further attention before these new therapies, if proven effective, can be implemented in clinical practice. The results may help in the design of care pathways for genetic interventions for these and other rare genetic movement disorders.
Assuntos
Terapia Genética , Doença de Huntington , Pesquisa Qualitativa , Ataxias Espinocerebelares , Humanos , Doença de Huntington/genética , Doença de Huntington/terapia , Doença de Huntington/psicologia , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/terapia , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Terapia Genética/métodos , IdosoRESUMO
BACKGROUND: Cerebellar ataxias comprise sporadic and genetic etiologies. Ataxia may also be a presenting feature in hereditary spastic paraplegias (HSPs). OBJECTIVE: To report a descriptive analysis of the frequency of different forms of cerebellar ataxia evaluated over 17 years in the Ataxia Unit of Universidade Federal de São Paulo, Brazil. METHODS: Charts of patients who were being followed from January 2007 to December 2023 were reviewed. We used descriptive statistics to present our results as frequencies and percentages of the overall analysis. Diagnosed patients were classified according to the following 9 groups: sporadic ataxia, spinocerebellar ataxias (SCAs), other autosomal dominant cerebellar ataxias, autosomal recessive cerebellar ataxias (ARCAs), mitochondrial ataxias, congenital ataxias, X-linked ataxias, HSPs, and others. RESULTS: There were 1,332 patients with ataxias or spastic paraplegias. Overall, 744 (55.85%) of all cases were successfully diagnosed: 101 sporadic ataxia, 326 SCAs, 20 of other autosomal dominant cerebellar ataxias, 186 ARCAs, 6 X-linked ataxias, 2 mitochondrial ataxias, 4 congenital ataxias, and 51 HSPs. CONCLUSION: This study describes the frequency of cerebellar ataxias in a large group of patients followed for the past 17 years, of whom 55% obtained a definitive clinical or molecular diagnosis. Future demographic surveys in Brazil or Latin American remain necessary.
ANTECEDENTES: Ataxias cerebelares compreendem as etiologias esporádicas e genéticas. Ataxia também pode ser uma característica das paraplegias espásticas hereditárias (HSPs). OBJETIVO: Relatar uma análise descritiva da frequência das diferentes formas de ataxias cerebelares avaliadas ao longo de 17 anos no Setor da Ataxias da Universidade Federal de São Paulo, Brasil. MéTODOS: Prontuários de pacientes acompanhados de janeiro de 2007 a dezembro de 2023 foram revisados. Usamos análise descritiva para apresentar nossos resultados como frequências e percentuais. Os pacientes foram classificados de acordo com os 9 grupos seguintes: ataxias esporádicas, ataxias espinocerebelares (SCA), outras ataxias cerebelares autossômicas dominantes, ataxias cerebelares autossômicas recessivas (ARCA), ataxias mitocondriais, ataxias congênitas, ataxias ligadas ao X, PEH e outros. RESULTADOS: Foram avaliados 1.332 pacientes. Desse total, 744 tiveram um diagnóstico definitivo: 101 ataxias esporádicas, 326 SCA, 20 outras ataxias cerebelares autossômicas dominantes, 186 (ARCA), 6 ataxias ligadas ao X, 2 ataxias mitocondriais, 4 ataxias congênitas e 51 HSP. CONCLUSãO: Esse estudo descreve a frequência e a etiologia das ataxias em um grande grupo de pacientes acompanhados nos últimos 17 anos, dos quais 55% obtiveram diagnóstico clínico ou molecular definitivos. Estudos demográficos futuros do Brasil ou da América Latina continuam sendo necessários.
Assuntos
Ataxia Cerebelar , Humanos , Brasil/epidemiologia , Feminino , Masculino , Adulto , Ataxia Cerebelar/epidemiologia , Ataxia Cerebelar/genética , Pessoa de Meia-Idade , Adolescente , Criança , Adulto Jovem , Estudos Retrospectivos , Pré-Escolar , Idoso , Ataxias Espinocerebelares/epidemiologia , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/congênitoRESUMO
We evaluated the efficacy and safety of 1-year treatment with nilotinib (Tasigna®) in patients with autosomal dominant spinocerebellar ataxia (ADSCA) and the factors associated with responsiveness. From an institutional cohort, patients with ADSCA who completed a 1-year treatment with nilotinib (150-300 mg/day) were included. Ataxia severity was assessed using the Scale for the Rating and Assessment of Ataxia (SARA), scores at baseline and 1, 3, 6, and 12 months. A subject was categorized 'responsive' when the SARA score reduction at 12 M was > 0. Pretreatment serum proteomic analysis included subjects with the highest (n = 5) and lowest (n = 5) SARA score change at 12 months and five non-ataxia controls. Thirty-two subjects (18 [56.2%] females, median age 42 [30-49.5] years) were included. Although SARA score at 12 M did not significantly improve in overall population, 20 (62.5%) subjects were categorized as responsive. Serum proteomic analysis identified 4 differentially expressed proteins, leucine-rich alpha-2-glycoprotein (LRG1), vitamin-D binding protein (DBP), and C4b-binding protein (C4BP) beta and alpha chain, which are involved in the autophagy process. This preliminary data suggests that nilotinib might improve ataxia severity in some patients with ADSCA. Serum protein markers might be a clue to predict the response to nilotinib.Trial Registration Information: Effect of Nilotinib in Cerebellar Ataxia Patients (NCT03932669, date of submission 01/05/2019).
Assuntos
Pirimidinas , Ataxias Espinocerebelares , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteômica/métodos , Pirimidinas/uso terapêutico , Ataxias Espinocerebelares/tratamento farmacológico , Ataxias Espinocerebelares/genética , Resultado do TratamentoRESUMO
BACKGROUND: Autosomal recessive spastic ataxia ofCharlevoix-Saguenay (ARSACS) is a rare neurodegenerative disorder characterizedby early-onset cerebellar ataxia, peripheral sensorimotor neuropathy, and lowerlimb spasticity. We present clinical andgenetic data of the first Bulgarian patients diagnosed with ARSACS by wholeexome sequencing (WES). METHODS: Variant filtering was performed usinglocally established pipeline and the selected variants were analysed by Sangersequencing. All patients underwent clinical examination and testingincluding the standard rating scales for spastic paraplegia and ataxia. RESULTS: Five different SACS gene variants, three of which novel, have been identified inpatients from three different ethnic groups. In addition to the classicalclinical triad, brain MRI revealed cerebellar atrophy, linear pontineT2-hypointensities, and hyperintense rim lateral tothalamus combined with retinal nerve fiber layer thickening on opticcoherence tomography (OCT). CONCLUSION: We expand the mutation, geographic, and phenotypic spectrum of ARSACS, adding Bulgaria to the world map of the disease, and drawing attention to the fact that it is still misdiagnosed. We demonstrated that brain MRI and OCT are necessary clinical tests for ARSACS diagnosis, even if one of the cardinal clinical features is lacking.
Assuntos
Proteínas de Choque Térmico , Espasticidade Muscular , Ataxias Espinocerebelares , Humanos , Masculino , Bulgária , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/patologia , Ataxias Espinocerebelares/congênito , Feminino , Espasticidade Muscular/genética , Espasticidade Muscular/patologia , Espasticidade Muscular/diagnóstico , Espasticidade Muscular/diagnóstico por imagem , Proteínas de Choque Térmico/genética , Fenótipo , Criança , Adulto , Mutação , Adolescente , Imageamento por Ressonância MagnéticaRESUMO
BACKGROUND: Spinocerebellar ataxia 4 (SCA4), characterized in 1996, features adult-onset ataxia, polyneuropathy, and linkage to chromosome 16q22.1; its underlying mutation has remained elusive. OBJECTIVE: To explore the radiological and neuropathological abnormalities in the entire neuroaxis in SCA4 and search for its mutation. METHODS: Three Swedish families with undiagnosed ataxia went through clinical, neurophysiological, and neuroimaging tests, including PET studies and genetic investigations. In four cases, neuropathological assessments of the neuroaxis were performed. Genetic testing included short read whole genome sequencing, short tandem repeat analysis with ExpansionHunter de novo, and long read sequencing. RESULTS: Novel features for SCA4 include dysautonomia, motor neuron affection, and abnormal eye movements. We found evidence of anticipation; neuroimaging demonstrated atrophy in the cerebellum, brainstem, and spinal cord. [18F]FDG-PET demonstrated brain hypometabolism and [11C]Flumazenil-PET reduced binding in several brain lobes, insula, thalamus, hypothalamus, and cerebellum. Moderate to severe loss of Purkinje cells in the cerebellum and of motor neurons in the anterior horns of the spinal cord along with pronounced degeneration of posterior tracts was also found. Intranuclear, mainly neuronal, inclusions positive for p62 and ubiquitin were sparse but widespread in the CNS. This finding prompted assessment for nucleotide expansions. A polyglycine stretch encoding GGC expansions in the last exon of the zink finger homeobox 3 gene was identified segregating with disease and not found in 1000 controls. CONCLUSIONS: SCA4 is a neurodegenerative disease caused by a novel GGC expansion in the coding region of ZFHX3, and its spectrum is expanded to include dysautonomia and neuromuscular manifestations.
Assuntos
Proteínas de Homeodomínio , Ataxias Espinocerebelares , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas de Homeodomínio/genética , Linhagem , Tomografia por Emissão de Pósitrons , Disautonomias Primárias/genética , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/diagnóstico por imagem , Suécia , Expansão das Repetições de Trinucleotídeos/genéticaRESUMO
OBJECTIVE: Transcranial sonography (TCS) is a noninvasive neuroimaging technique, visualizing deep brain structures and the ventricular system. Although widely employed in diagnosing various movement disorders, such as Parkinson's disease and dystonia, by detecting disease-specific abnormalities, the specific characteristics of the TCS in cerebellar ataxia remain inconclusive. We aimed to assess the potential value of TCS in patients with cerebellar ataxias for disease diagnosis and severity assessment. METHODS: TCS on patients with genetic and acquired cerebellar ataxia, including 94 with spinocerebellar ataxias (SCAs) containing 10 asymptomatic carriers, 95 with cerebellar subtype of multiple system atrophy (MSA-C), and 100 healthy controls (HC), was conducted. Assessments included third ventricle width, substantia nigra (SN) and lentiform nucleus (LN) echogenicity, along with comprehensive clinical evaluations and genetic testing. RESULTS: The study revealed significant TCS abnormalities in patients with cerebellar ataxia, such as enlarged third ventricle widths and elevated rates of hyperechogenic SN and LN. TCS showed high accuracy in distinguishing patients with SCA or MSA-C from HC, with an AUC of 0.870 and 0.931, respectively. TCS abnormalities aided in identifying asymptomatic SCA carriers, effectively differentiating them from HC, with an AUC of 0.725. Furthermore, third ventricle width was significantly correlated with SARA and ICARS scores in patients with SCA3 and SCOPA-AUT scores in patients with MSA-C. The SN area and SARA or ICARS scores in patients with SCA3 were also positively correlated. INTERPRETATION: Our findings illustrate remarkable TCS abnormalities in patients with cerebellar ataxia, serving as potential biomarkers for clinical diagnosis and progression assessment.
Assuntos
Ataxia Cerebelar , Ultrassonografia Doppler Transcraniana , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Ultrassonografia Doppler Transcraniana/métodos , Ultrassonografia Doppler Transcraniana/normas , Ataxia Cerebelar/diagnóstico por imagem , Adulto , Idoso , Atrofia de Múltiplos Sistemas/diagnóstico por imagem , Ataxias Espinocerebelares/diagnóstico por imagem , Substância Negra/diagnóstico por imagem , Biomarcadores , Terceiro Ventrículo/diagnóstico por imagemRESUMO
OBJECTIVE: Biallelic mutations in PRDX3 have been linked to autosomal recessive spinocerebellar ataxia type 32. In this study, which aims to contribute to the growing body of knowledge on this rare disease, we identified two unrelated patients with mutations in PRDX3. We explored the impact of PRDX3 mutation in patient skin fibroblasts and the role of the gene in neurodevelopment. METHODS: We performed trio exome sequencing that identified mutations in PRDX3 in two unrelated patients. We also performed functional studies in patient skin fibroblasts and generated a "crispant" zebrafish (Danio rerio) model to investigate the role of the gene during nervous system development. RESULTS: Our study reports two additional patients. Patient 1 is a 19-year-old male who showed a novel homozygous c.525_535delGTTAGAAGGTT (p. Leu176TrpfsTer11) mutation as the genetic cause of cerebellar ataxia. Patient 2 is a 20-year-old male who was found to present the known c.425C>G/p. Ala142Gly variant in compound heterozygosity with the p. Leu176TrpfsTer11 one. While the fibroblast model failed to recapitulate the pathological features associated with PRDX3 loss of function, our functional characterization of the prdx3 zebrafish model revealed motor defects, increased susceptibility to reactive oxygen species-triggered apoptosis, and an impaired oxygen consumption rate. CONCLUSIONS: We identified a new variant, thereby expanding the genetic spectrum of PRDX3-related disease. We developed a novel zebrafish model to investigate the consequences of prdx3 depletion on neurodevelopment and thus offered a potential new tool for identifying new treatment opportunities.
Assuntos
Peixe-Zebra , Humanos , Masculino , Animais , Adulto Jovem , Fibroblastos , Mutação , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/congênitoRESUMO
BACKGROUND: Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS) and Spastic Paraplegia Type 7 (SPG7) are paradigmatic spastic ataxias (SPAX) with suggested white matter (WM) involvement. Aim of this work was to thoroughly disentangle the degree of WM involvement in these conditions, evaluating both macrostructure and microstructure via the analysis of diffusion MRI (dMRI) data. MATERIAL AND METHODS: In this multi-center prospective study, ARSACS and SPG7 patients and Healthy Controls (HC) were enrolled, all undergoing a standardized dMRI protocol and a clinimetrics evaluation including the Scale for the Assessment and Rating of Ataxia (SARA). Differences in terms of WM volume or global microstructural WM metrics were probed, as well as the possible occurrence of a spatially defined microstructural WM involvement via voxel-wise analyses, and its correlation with patients' clinical status. RESULTS: Data of 37 ARSACS (M/F = 21/16; 33.4 ± 12.4 years), 37 SPG7 (M/F = 24/13; 55.7 ± 10.7 years), and 29 HC (M/F = 13/16; 42.1 ± 17.2 years) were analyzed. While in SPG7, only a mild mean microstructural damage was found compared to HC, ARSACS patients present a severe WM involvement, with a reduced global volume (p < 0.001), an alteration of all microstructural metrics (all with p < 0.001), without a spatially defined pattern of damage but with a prominent involvement of commissural fibers. Finally, in ARSACS, a correlation between microstructural damage and SARA scores was found (p = 0.004). CONCLUSION: In ARSACS, but not SPG7 patients, we observed a complex and multi-faced involvement of brain WM, with a clinically meaningful widespread loss of axonal and dendritic integrity, secondary demyelination and, overall, a reduction in cellularity and volume.
Assuntos
Espasticidade Muscular , Ataxias Espinocerebelares , Substância Branca , Humanos , Masculino , Feminino , Adulto , Substância Branca/diagnóstico por imagem , Substância Branca/patologia , Pessoa de Meia-Idade , Ataxias Espinocerebelares/diagnóstico por imagem , Ataxias Espinocerebelares/patologia , Espasticidade Muscular/diagnóstico por imagem , Espasticidade Muscular/patologia , Adulto Jovem , Estudos Prospectivos , Idoso , Paraplegia Espástica Hereditária/diagnóstico por imagem , Paraplegia Espástica Hereditária/patologia , Imagem de Difusão por Ressonância Magnética , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Imageamento por Ressonância Magnética , Deficiência Intelectual , Atrofia ÓpticaRESUMO
BACKGROUND: Autosomal-dominant spinocerebellar ataxia (ADCA) due to intronic GAA repeat expansion in FGF14 (SCA27B) is a recent, relatively common form of late-onset ataxia. OBJECTIVE: Here, we aimed to: (1) investigate the relative frequency of SCA27B in different clinically defined disease subgroups with late-onset ataxia collected among 16 tertiary Italian centers; (2) characterize phenotype and diagnostic findings of patients with SCA27B; (3) compare the Italian cohort with other cohorts reported in recent studies. METHODS: We screened 396 clinically diagnosed late-onset cerebellar ataxias of unknown cause, subdivided in sporadic cerebellar ataxia, ADCA, and multisystem atrophy cerebellar type. We identified 72 new genetically defined subjects with SCA27B. Then, we analyzed the clinical, neurophysiological, and imaging features of 64 symptomatic cases. RESULTS: In our cohort, the prevalence of SCA27B was 13.4% (53/396) with as high as 38.5% (22/57) in ADCA. The median age of onset of SCA27B patients was 62 years. All symptomatic individuals showed evidence of impaired balance and gait; cerebellar ocular motor signs were also frequent. Episodic manifestations at onset occurred in 31% of patients. Extrapyramidal features (17%) and cognitive impairment (25%) were also reported. Brain magnetic resonance imaging showed cerebellar atrophy in most cases (78%). Pseudo-longitudinal assessments indicated slow progression of ataxia and minimal functional impairment. CONCLUSION: Patients with SCA27B in Italy present as an adult-onset, slowly progressive cerebellar ataxia with predominant axial involvement and frequent cerebellar ocular motor signs. The high consistency of clinical features in SCA27B cohorts in multiple populations paves the way toward large-scale, multicenter studies.
Assuntos
Progressão da Doença , Humanos , Pessoa de Meia-Idade , Itália/epidemiologia , Masculino , Feminino , Idoso , Estudos de Coortes , Ataxias Espinocerebelares/genética , Ataxias Espinocerebelares/diagnóstico por imagem , Ataxias Espinocerebelares/epidemiologia , Adulto , Ataxia Cerebelar/genética , Ataxia Cerebelar/epidemiologia , Ataxia Cerebelar/diagnóstico por imagem , Ataxia Cerebelar/fisiopatologia , Idade de Início , Fatores de Crescimento de Fibroblastos , Degenerações EspinocerebelaresRESUMO
Spinocerebellar ataxia type 10 (SCA10) is a rare autosomal dominant ataxia caused by a large expansion of the (ATTCT)n repeat in ATXN10. SCA10 was described in Native American and Asian individuals which prompted a search for an expanded haplotype to confirm a common ancestral origin for the expansion event. All patients with SCA10 expansions in our cohort share a single haplotype defined at the 5'-end by the minor allele of rs41524547, located ~35 kb upstream of the SCA10 expansion. Intriguingly, rs41524547 is located within the miRNA gene, MIR4762, within its DROSHA cleavage site and just outside the seed sequence for mir4792-5p. The world-wide frequency of rs41524547-G is less than 5% and found almost exclusively in the Americas and East Asia-a geographic distribution that mirrors reported SCA10 cases. We identified rs41524547-G(+) DNA from the 1000 Genomes/International Genome Sample Resource and our own general population samples and identified SCA10 repeat expansions in up to 25% of these samples. The reduced penetrance of these SCA10 expansions may be explained by a young (pre-onset) age at sample collection, a small repeat size, purity of repeat units, or the disruption of miR4762-5p function. We conclude that rs41524547-G is the most robust at-risk SNP allele for SCA10, is useful for screening of SCA10 expansions in population genetics studies and provides the most compelling evidence to date for a single, prehistoric origin of SCA10 expansions sometime prior to or during the migration of individuals across the Bering Land Bridge into the Americas.