A case report of COVID-19 positive Becker Muscular Dystrophy

Background: Becker and Duchenne muscular dystrophies constitute the most common inherited dystrophinopathies. The chronic steroid treatment predisposes them to any infection, hence, we sought to determine the current COVID-19 infection in them. We conducted an analysis on a real-world database to identify the effect of COVID-19 infection and identified a case of Becker muscular dystrophy who tested positive for COVID-19. For our analysis, we utilized Cerner Real-World DataTM that was provided through Cerner's HealtheDataLab research tool. Case report: A 63-year-old Caucasian male with Becker muscular dystrophy, hyperlipidemia, and atrial fibrillation, was hospitalized with COVID-19 infection. Our search revealed June 22, 2020, as the patient's COVID-19 service date when tested positive. The patient received antibiotics and supportive therapy during hospitalization. Intricate details like oxygen requirement, blood gas analysis, and mechanical ventilation could not be retrieved if used. The patient developed complications like sepsis, pneumonia, acute respiratory failure that resulted in prolonged hospitalization. Our data reported that the patient was alive during discharge. Conclusion: Although patient developed complications during hospitalization, no death from the COVID-19 infection was observed in our analysis.

Combining Protein Expression and Molecular Data Improves Mutation Characterization of Dystrophinopathies

Duchenne and Becker muscular dystrophy are X-linked recessive inherited disorders characterized by progressive weakness due to skeletal muscle degeneration. Different mutations in the DMD gene, which encodes for dystrophin protein, are responsible for these disorders. The aim of our study was to investigate the relationship between type, size, and location of the mutation that occurs in the DMD gene and their effect on dystrophin protein expression in a cohort of 40 male dystrophinopathy patients and nine females, possible carriers. We evaluated the expression of dystrophin by immunofluorescence and immunoblotting. The mutational spectrum of the DMD gene was established by MLPA for large copy number variants, followed by HRM analysis for point mutations and sequencing of samples with an abnormal melting profile. MLPA revealed 30 deletions (75%) and three duplications (7.5%). HRM analysis accounted for seven-point mutations (17.5%). We also report four novel small mutations (c. 8507G>T, c.3021delG, c.9563_9563+1insAGCATGTTTATGATACAGCA, c.7661-60T>A) in DMD gene. Our work shows that the DNA translational open reading frame and the location of the mutation both influence the expression of dystrophin and disease severity phenotype. The proposed algorithm used in this study demonstrates its accuracy for the characterization of dystrophinopathy patients.

Identifying the hub genes for Duchenne muscular dystrophy and Becker muscular dystrophy by weighted correlation network analysis

Background The goal of this study is to identify the hub genes for Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) via weighted correlation network analysis (WGCNA). Methods The gene expression profile of vastus lateralis biopsy samples obtained in 17 patients with DMD, 11 patients with BMD and 6 healthy individuals was downloaded from the Gene Expression Omnibus (GEO) database (GSE109178). After obtaining different expressed genes (DEGs) via GEO2R, WGCNA was conducted using R package, modules and genes that highly associated with DMD, BMD, and their age or pathology were screened. Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) enrichment analysis and protein–protein interaction (PPI) network analysis were also conducted. Hub genes and highly correlated clustered genes were identified using Search Tool for the Retrieval of Interacting Genes (STRING) and Cystoscape software. Results One thousand four hundred seventy DEGs were identified between DMD and control, with 1281 upregulated and 189 downregulated DEGs. Four hundred and twenty DEGs were found between BMD and control, with 157 upregulated and 263 upregulated DEGs. Fourteen modules with different colors were identified for DMD vs control, and 7 modules with different colors were identified for BMD vs control. Ten hub genes were summarized for DMD and BMD respectively, 5 hub genes were summarized for BMD age, 5 and 3 highly correlated clustered genes were summarized for DMD age and BMD pathology, respectively. In addition, 20 GO enrichments were found to be involved in DMD, 3 GO enrichments were found to be involved in BMD, 3 GO enrichments were found to be involved in BMD age. Conclusion In DMD, several hub genes were identified: C3AR1, TLR7, IRF8, FYB and CD33(immune and inflammation associated genes), TYROBP, PLEK, AIF1(actin reorganization associated genes), LAPTM5 and NT5E(cell death and arterial calcification associated genes, respectively). In BMD, a number of hub genes were identified: LOX, ELN, PLEK, IKZF1, CTSK, THBS2, ADAMTS2, COL5A1(extracellular matrix associated genes), BCL2L1 and CDK2(cell cycle associated genes).

Diagnostic Value of Dystrophin Immunostaining in the Diagnosis of Duchenne and Becker Muscular Dystrophy Patients

Background: Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are X-linked recessive muscular disorders caused by the absence or reduction of the muscle cytoskeletal protein dystrophin. Standard procedures to detect deletion and duplication of the DMD gene use Multiplex Ligation-Dependent Probe Amplification (MLPA). However, genetic testing, such as MLPA, is not covered by the national insurance scheme in Indonesia. Immunohistochemical (IHC) staining of dystrophin from muscle biopsy in the form of Formalin-Fixed Paraffin-Embedded (FFPE) specimens can be an alternative method to detect dystrophin expression in protein levels to establish the diagnosis of DMD or BMD. Objectives: To determinate sensitivity, specificity and accuracy of IHC analysis of dystrophin in DMD/BMD patient in comparison with the standard genetic testing, MLPA. Methods: Twenty-six patients enrolled in this study were clinically diagnosed as DMD/BMD in Dr. Sardjito Hospital and Universitas Gadjah Mada Academic Hospital. Genomic DNA was isolated from 3 mL of EDTA-peripheral whole blood samples. The deletion and duplication of DMD genes were detected by MLPA. IHC examination was performed using a specific antibody dystrophin (DYS2). Complete loss of dystrophin staining indicated DMD, while partial loss of dystrophin staining indicated BMD. MLPA result was used as the gold standard to determine sensitivity, specificity, and accuracy of IHC technique using a 2x2 table. Results: MLPA results revealed 18 (18/26; 69.3%) patients with deletion and 3 (3/26; 11.5%) patients with duplication. Five (5/26; 19.2%) patients who showed no deletion nor duplication were excluded from the analysis. Among 21 patients with deletion or duplication, 18 (18/21; 85.7%) patients were out-of-frame (DMD) and 3 (3/21; 14.3%) patients were in-frame (BMD). Six patients showed a discrepancy between the IHC and MLPA results with 9.5% (2/21) false positive and 19% (4/21) false negative. The sensitivity of dystrophin IHC was 77.78%, specificity 33.33%, positive predictive value 87.5%, negative predictive value 20%, and accuracy 71.43%. Conclusion: Muscle biopsy followed by IHC can be one of the diagnostic tools to diagnose BMD or DMD, with high sensitivity. The protein-based strategy is probably the most efficient way to approach the diagnosis of Duchenne and Becker muscular dystrophy in limited health care settings.

Differentiation of Pediatric-Onset Duchenne and Becker Muscular Dystrophy Subphenotypes Using the Muscular Dystrophy Surveillance Tracking and Research Network (MD STARnet)

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) phenotypes are used to describe disease progression in affected individuals. However, considerable heterogeneity has been observed across and within these two phenotypes, suggesting a spectrum of severity rather than distinct conditions. Characterizing the phenotypes and subphenotypes aids researchers in the design of clinical studies and clinicians in providing anticipatory guidance to affected individuals and their families. Using data from the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet), we used K-means cluster analysis to group phenotypically similar males with pediatric-onset dystrophinopathy. We identified four dystrophinopathy clusters: Classical BMD, Classical DMD, late ambulatory DMD, and severe DMD. The clusters that we identified align with both ‘classical’ and ‘non-classical’ dystrophinopathy described in the literature. Individuals with dystrophinopathies have heterogenous clinical presentations that cluster into phenotypically similar groups. Use of clinically-derived phenotyping may provide a clearer understanding of disease trajectories, reduce variability in study results, and prevent exclusion of certain cohorts from analysis. Findings from studying subphenotypes may ultimately improve our ability to predict disease progression.

Candidate gene modifiers of dystrophinopathy identified by the uniform application of genome-wide datasets to novel GWAS-identified loci

Although the major determinant of disease severity in patients with severe Duchenne muscular dystrophy (DMD) or milder Becker muscular dystrophy (BMD) is whether their dystrophin gene (DMD) mutation disrupts the mRNA reading frame or allows expression of a partially functional protein, other genes have been proposed or demonstrated to modify the severity of disease progression. In a companion paper to this one, we describe our novel approaches to genome-wide association study (GWAS) of loss of ambulation (LOA) in the largest genome-wide search to date for loci influencing disease severity in DMD patients. Candidate regulatory SNPs that modify disease progression were identified using an evidential statistical paradigm and here we present a uniform application of recent functional genomic datasets to explore the potential functional impact of the top six candidate regions with PPLD scores of ≥0.4. The results of this analysis of the largest DMD GWAS survey to date elucidate recurrent and potentially new pathways for intervention in the dystrophinopathies.

Non-compaction cardiomyopathy, Becker muscular dystrophy, neuropathy and recurrent syncope

We present the case of a 50-year-old man presenting with new heart failure symptoms. He had no evidence of any ischaemic cardiomyopathy, however, further cardiac imaging showed a left ventricular non-compaction cardiomyopathy. He was noted to have muscular weakness and an exhaustive search for associated comorbidities yielded a diagnosis of Becker muscular dystrophy. In this report, we review the pathophysiology, comorbidities and diagnostic workup in patients presenting with left ventricular non-compaction in the context of dystrophinopathy. Ultimately, we suggest the consideration of rare cardiomyopathies in all patients presenting with neuromuscular syndromes and vice versa.