scholarly journals Highly Elevated Prevalence of Spinobulbar Muscular Atrophy in Indigenous Communities in Canada Due to a Founder Effect

2021 ◽  
Vol 7 (4) ◽  
pp. e607
Author(s):  
Jamie N. Leckie ◽  
Matthew M. Joel ◽  
Kristina Martens ◽  
Alexandra King ◽  
Malcolm King ◽  
...  
Keyword(s):  
Founder Effect ◽  
Muscular Atrophy ◽  
Population Data ◽  
Indigenous Communities ◽  
Neuromuscular Disorder ◽  
Disease Prevalence ◽  
Unique Haplotype ◽  
Spinobulbar Muscular Atrophy ◽  
Statistics Canada ◽  
Disease Haplotype

ObjectiveSpinobulbar muscular atrophy (SBMA) is an X-linked adult-onset neuromuscular disorder that causes progressive weakness and androgen insensitivity in hemizygous males. This condition is reported to be extremely rare, but has higher prevalence in certain populations due to multiple founder effects. Anecdotal observations of a higher prevalence of SBMA in patients of Indigenous descent in Saskatchewan led us to perform this study, to estimate the disease prevalence, and to attempt to identify a founder effect.MethodsFor our prevalence estimation, we identified patients with confirmed SBMA diagnosis from the Saskatoon neuromuscular clinic database for comparison with population data available from Statistics Canada. For our haplotype analysis, participants with SBMA were recruited from 2 neuromuscular clinics, as well as 5 control participants. Clinical data were collected, as well as a DNA sample using saliva kits. We performed targeted quantification of DXS1194, DXS1111, DXS135, and DXS1125 microsatellite repeats and the AR GGC repeat to attempt to identify a disease haplotype and compare it with prior studies.ResultsWe estimate the prevalence of SBMA among persons of Indigenous descent in Saskatchewan as 14.7 per 100,000 population. Although we believe that this is an underestimate, this still appears to be the highest population prevalence for SBMA in the world. A total of 21 participants were recruited for the haplotype study, and we identified a unique haplotype that was shared among 13 participants with Indigenous ancestry. A second shared haplotype was identified in 2 participants, which may represent a second founder haplotype, but this would need to be confirmed with future studies.ConclusionsWe describe a very high prevalence of SBMA in western Canadians of Indigenous descent, which appears to predominantly be due to a founder effect. This necessitates further studies of SBMA in these populations to comprehensively ascertain the disease prevalence and allow appropriate allocation of resources to support individuals living with this chronic disease.

scholarly journals Side chain to main chain hydrogen bonds stabilize a polyglutamine helix in the activation domain of a transcription factor

2018 ◽  
Author(s):  
Albert Escobedo ◽  
Busra Topal ◽  
Micha Ben Achim Kunze ◽  
Juan Aranda ◽  
Giulio Chiesa ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Hydrogen Bonds ◽  
Transcriptional Activity ◽  
Main Chain ◽  
Muscular Atrophy ◽  
Helical Structure ◽  
Structural Basis ◽  
Tract Length ◽  
Spinobulbar Muscular Atrophy ◽  
Polyq Tract

Polyglutamine (polyQ) tracts are regions of low sequence complexity of variable length found in more than one hundred human proteins. These tracts are frequent in activation domains of transcription factors and their length often correlates with transcriptional activity. In addition, in nine proteins, tract elongation beyond specific thresholds causes polyQ disorders. To study the structural basis of the association between tract length, transcriptional activity and disease, here we addressed how the conformation of the polyQ tract of the androgen receptor (AR), a transcription factor associated with the polyQ disease spinobulbar muscular atrophy (SBMA), depends on its length. We found that the tract folds into a helical structure stabilized by unconventional hydrogen bonds between glutamine side chains and main chain carbonyl groups. These bonds are bifurcate with the conventional main chain to main chain hydrogen bonds stabilizing α-helices. In addition, since tract elongation provides additional interactions, the helicity of the polyQ tract directly correlates with its length. These findings suggest a plausible rationale for the association between polyQ tract length and AR transcriptional activity and have implications for establishing the mechanistic basis of SBMA.

scholarly journals The Use of Korean Medicine to Treat Patients with Spinobulbar Muscular Atrophy, Kennedy’s Disease - A Case Study

2017 ◽  
Vol 20 (1) ◽  
pp. 57-60
Author(s):  
Sungchul Kim ◽  
Seongjin Lee ◽  
Eunhye Cha ◽  
Jongcheol Lee ◽  
Jongdeok Lee ◽  
...  
Keyword(s):  
Muscular Atrophy ◽  
Korean Medicine ◽  
Spinobulbar Muscular Atrophy ◽  
Kennedy’S Disease ◽  
Kennedy's Disease

Laryngospasm: An underdiagnosed symptom of X-linked spinobulbar muscular atrophy

Neurology ◽  
2005 ◽  
Vol 64 (4) ◽  
pp. 753-754 ◽  
Author(s):  
A.-D. Sperfeld ◽  
C. O. Hanemann ◽  
A. C. Ludolph ◽  
J. Kassubek
Keyword(s):  
Muscular Atrophy ◽  
Spinobulbar Muscular Atrophy

Decision-Making Regarding Ventilator Support in Children with SMA Type 1—A Cross-Sectional Survey among Physicians

2019 ◽  
Vol 50 (06) ◽  
pp. 359-366
Author(s):  
Astrid Pechmann ◽  
Thorsten Langer ◽  
Janbernd Kirschner
Keyword(s):  
Decision Making ◽  
Mechanical Ventilation ◽  
Informed Consent ◽  
Muscular Atrophy ◽  
Neuromuscular Disorder ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Ventilator Support ◽  
Case Vignettes

AbstractSpinal muscular atrophy (SMA) is a neuromuscular disorder characterized by muscle atrophy and severe proximal muscle weakness. In the absence of curative treatment, it has been controversial whether critically ill infants with SMA type 1 should receive ventilator support. The aim of this study was to investigate the process of decision-making regarding ventilator support in children with SMA type 1 from the perspectives of physicians. A web-based survey with 17 questions and 2 case vignettes was conducted in 671 physicians in Germany and Switzerland from 12/2016 to 03/2017. The survey focused on factors influencing the decision about ventilator support and the content in informed consent discussions. Additionally, physicians were asked about their general attitude towards mechanical ventilation in children with SMA type 1 and their hypothetical clinical management in emergency settings using case vignettes. Hundred and sixty-five physicians participated in the survey (50.3% child neurologists, 18.8% specialists for ventilator support, 6.1% pediatric palliative care physicians, and 6.1% with more than one of these specializations). Of all physicians, 44.2% confirmed to have experience with SMA type 1 patients using ventilator support. In summary, our results show that physicians' attitudes and experiences about mechanical ventilation in children with SMA type 1 vary considerably and are likely to influence the outcome in informed consent discussions and the hypothetical management in emergency settings.

scholarly journals Genomic analysis of a spinal muscular atrophy (SMA) discordant family identifies a novel mutation in TLL2, an activator of growth differentiation factor 8 (myostatin): a case report

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Jianping Jiang ◽  
Jinwei Huang ◽  
Jianlei Gu ◽  
Xiaoshu Cai ◽  
Hongyu Zhao ◽  
...  
Keyword(s):  
Spinal Muscular Atrophy ◽  
De Novo ◽  
Muscular Atrophy ◽  
Novel Mutation ◽  
Genomic Analysis ◽  
Neuromuscular Disorder ◽  
De Novo Mutation ◽  
Compound Heterozygous ◽  
Mice Model ◽  
Compound Heterozygous Mutations

Abstract Background Spinal muscular atrophy (SMA) is a rare neuromuscular disorder threating hundreds of thousands of lives worldwide. And the severity of SMA differs among different clinical types, which has been demonstrated to be modified by factors like SMN2, SERF1, NAIP, GTF2H2 and PLS3. However, the severities of many SMA cases, especially the cases within a family, often failed to be explained by these modifiers. Therefore, other modifiers are still waiting to be explored. Case presentation In this study, we presented a rare case of SMA discordant family with a mild SMA male patient and a severe SMA female patient. The two SMA cases fulfilled the diagnostic criteria defined by the International SMA Consortium. With whole exome sequencing, we confirmed the heterozygous deletion of exon7 at SMN1 on the parents’ genomes and the homozygous deletions on the two patients’ genomes. The MLPA results confirmed the deletions and indicated that all the family members carry two copies of SMN2, SERF1, NAIP and GTF2H2. Further genomic analysis identified compound heterozygous mutations at TLL2 on the male patient’s genome, and compound heterozygous mutations at VPS13A and the de novo mutation at AGAP5 on female patient’s genome. TLL2 is an activator of myostatin, which negatively regulates the growth of skeletal muscle tissue. Mutation in TLL2 has been proved to increase muscular function in mice model. VPS13A encodes proteins that control the cycling of proteins through the trans-Golgi network to endosomes, lysosomes and the plasma membrane. And AGAP5 was reported to have GTPase activator activity. Conclusions We reported a case of SMA discordant family and identified mutations at TLL2, VPS13A and AGAP5 on the patients’ genomes. The mutations at TLL2 were predicted to be pathogenic and are likely to alleviate the severity of the male SMA patient. Our finding broadens the spectrum of genetic modifiers of SMA and will contribute to accurate counseling of SMA affected patients and families.

scholarly journals P.068 Abnormal fatty acid metabolism is a feature of spinal muscular atrophy

2019 ◽  
Vol 46 (s1) ◽  
pp. S32
Author(s):  
M Deguise ◽  
A Beauvais ◽  
G Baranello ◽  
C Pileggi ◽  
C Mastella ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Metabolism ◽  
High Resolution ◽  
Mouse Model ◽  
Spinal Muscular Atrophy ◽  
Muscular Atrophy ◽  
Liver Steatosis ◽  
Neuromuscular Disorder ◽  
Glycogen Depletion ◽  
Preclinical Animal Models

Background: Spinal muscular atrophy (SMA) is a children’s neuromuscular disorder. Although motor neuron loss is a major feature of the disease, we have identified fatty acid abnormalities in SMA patients and in preclinical animal models, suggesting metabolic perturbation is also an important component of SMA. Methods: Biochemical, histological, proteomic, and high resolution respirometry were used. Results: SMA patients are more susceptible to dyslipidemia than the average population as determined by a standard lipid profile in a cohort of 72 pediatric patients. As well, we observed a non-alcoholic liver disease phenotype in apreclinical mouse model. Denervation alone was not sufficient to induce liver steatosis, as a mouse model of ALS, did not develop fatty liver. Hyperglucagonemia in Smn2B/-mice could explain the hepatic steatosis by increasing plasma substrate availability via glycogen depletion and peripheral lipolysis. Proteomic analysis identified mitochondrion and lipid metabolism as major clusters. Alterations in mitochondrial function were revealed by high-resolution respirometry. Finally, low-fat diets led to increased survival in Smn2B/-mice. Conclusions: These results provide strong evidence for lipid metabolism defects in SMA. Further investigation will be required to establish the primary mechanism of these alterations and understand how they lead to additional co-morbidities in SMA patients.

scholarly journals The RNA Binding Protein hnRNP Q Modulates the Utilization of Exon 7 in the Survival Motor Neuron 2 (SMN2) Gene

2008 ◽  
Vol 28 (22) ◽  
pp. 6929-6938 ◽  
Author(s):  
Hung-Hsi Chen ◽  
Jan-Growth Chang ◽  
Ruei-Min Lu ◽  
Tsui-Yi Peng ◽  
Woan-Yuh Tarn
Keyword(s):  
Rna Binding ◽  
Muscular Atrophy ◽  
Rna Binding Protein ◽  
Neuromuscular Disorder ◽  
Mrna Splicing ◽  
Survival Motor Neuron ◽  
Smn2 Gene ◽  
Smn Protein ◽  
High Level ◽  
Precursor Mrna

ABSTRACT Spinal muscular atrophy (SMA) is a recessive neuromuscular disorder caused by the homozygous loss of the SMN1 gene. The human SMN2 gene has a C-to-T transition at position +6 of exon 7 and thus produces exon 7-skipping mRNAs. However, we observed an unexpectedly high level of exon 7-containing SMN2 transcripts as well as SMN protein in testis of smn −/− SMN2 transgenic mice. Using affinity chromatography, we identified several SMN RNA-associating proteins in mouse testis and human HeLa cells, including hnRNP Q. The major hnRNP Q isoform, Q1, directly bound SMN exon 7 in the vicinity of nucleotide +6. Overexpression of hnRNP Q1 promoted the inclusion of exon 7 in SMN2, probably by activating the use of its upstream 3′ splice site. However, the minor isoforms Q2/Q3 could antagonize the activity of hnRNP Q1 and induced exon 7 exclusion. Intriguingly, enhanced exon 7 inclusion was also observed upon concomitant depletion of three hnRNP Q isoforms. Thus, differential expression of hnRNP Q isoforms may result in intricate control of SMN precursor mRNA splicing. Here, we demonstrate that hnRNP Q is a splicing modulator of SMN, further underscoring the potential of hnRNP Q as a therapeutic target for SMA.

scholarly journals Native Functions of the Androgen Receptor Are Essential to Pathogenesis in a Drosophila Model of Spinobulbar Muscular Atrophy

Neuron ◽  
2010 ◽  
Vol 67 (6) ◽  
pp. 936-952 ◽  
Author(s):  
Natalia B. Nedelsky ◽  
Maria Pennuto ◽  
Rebecca B. Smith ◽  
Isabella Palazzolo ◽  
Jennifer Moore ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Muscular Atrophy ◽  
Spinobulbar Muscular Atrophy ◽  
Drosophila Model

scholarly journals Disease mechanism, biomarker and therapeutics for spinal and bulbar muscular atrophy (SBMA)

2020 ◽  
Vol 91 (10) ◽  
pp. 1085-1091
Author(s):  
Atsushi Hashizume ◽  
Kenneth H Fischbeck ◽  
Maria Pennuto ◽  
Pietro Fratta ◽  
Masahisa Katsuno
Keyword(s):  
Motor Neurons ◽  
Animal Studies ◽  
Muscular Atrophy ◽  
Neuromuscular Disorder ◽  
Nuclear Accumulation ◽  
Gene Encoding ◽  
Metabolic Switch ◽  
Hand Tremor ◽  
Hormonal Manipulation ◽  
Biochemical Indices

Spinal and bulbar muscular atrophy (SBMA) is a hereditary neuromuscular disorder caused by CAG trinucleotide expansion in the gene encoding the androgen receptor (AR). In the central nervous system, lower motor neurons are selectively affected, whereas pathology of patients and animal models also indicates involvement of skeletal muscle including loss of fast-twitch type 2 fibres and increased slow-twitch type 1 fibres, together with a glycolytic-to-oxidative metabolic switch. Evaluation of muscle and fat using MRI, in addition to biochemical indices such as serum creatinine level, are promising biomarkers to track the disease progression. The serum level of creatinine starts to decrease before the onset of muscle weakness, followed by the emergence of hand tremor, a prodromal sign of the disease. Androgen-dependent nuclear accumulation of the polyglutamine-expanded AR is an essential step in the pathogenesis, providing therapeutic opportunities via hormonal manipulation and gene silencing with antisense oligonucleotides. Animal studies also suggest that hyperactivation of Src, alteration of autophagy and a mitochondrial deficit underlie the neuromuscular degeneration in SBMA and provide alternative therapeutic targets.

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