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At least 19 recordsLinked to original sources

PubMed2025

Rethinking the pathogenicity of intragenic DMD duplications detected by carrier screening: High prevalence of nontandem duplications revealed by long-read sequencing.

PURPOSE: The pathogenicity of intragenic duplications depends on their structural configuration. Tandem duplications often disrupt reading frames and cause gene loss of function, whereas interspersed (nontandem) duplications are largely benign. When the configuration cannot be determined, current guidelines presume a tandem structure, leading to some laboratories automatically classifying such variants as likely pathogenic or pathogenic. This study evaluates the validity of this presumption for DMD, in patients with and without clinical indications of dystrophinopathy. METHODS: We performed high-coverage long-read genome sequencing on 15 patients with intragenic DMD duplications. A total of 4 patients had clinically indicated dystrophinopathy testing, whereas in the remaining 11 patients, the duplications were detected without clear indications of dystrophinopathy (eg, through carrier screening). RESULTS: All 4 patients with clinical indications had tandem duplications. In contrast, 64% (7/11) of the cases without such indications had interspersed duplications, with 4 subsequently reclassified as likely benign, 2 (likely) pathogenic, and 1 uncertain. These duplications were often complex, involving coduplications or codeletions with other regions. CONCLUSION: Our findings challenge the presumption that intragenic DMD duplications are predominantly in tandem. This highlights the need for a cautious variant interpretation approach, particularly in carrier screening and other settings in which variants are identified without indications of dystrophinopathy.

Humans↗

PubMed2026

MicroRNA-mRNA Networks in Skeletal Muscle of Tailored Pig Models for Dystrophinopathies.

BACKGROUND: Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are X-linked dystrophinopathies caused by mutations in the dystrophin (DMD) gene. A common DMD-causing mutation in humans is exon 52 deletion (DMDΔ52), which disrupts the reading frame and abolishes dystrophin expression. Therapeutic skipping of exon 51 or 53 can restore the reading frame, producing a truncated but functional protein and generating a BMD-like phenotype. Porcine models recapitulating DMDΔ52 (DMD) and DMDΔ51-52 (BMD-like) were used to identify molecular differences and condition-specific miRNA-mRNA networks. METHODS: Skeletal muscle (triceps brachii) from four DMD, four BMD, and five wild-type (WT) pigs at 3.5 months of age underwent stranded total RNA-seq and small RNA-seq. Differentially expressed mRNAs (|log2FC| ≥ 1, adj. p ≤ 0.05) and miRNAs (adj. p ≤ 0.05) were identified with DESeq2. miRNA-mRNA networks were constructed using RNAhybrid predictions (MFE < -25 kcal/mol, seed pairing) filtered by inverse Pearson correlation. RESULTS: Compared with WT, DMD muscle exhibited 1440 upregulated and 487 downregulated genes, characterized by strong repression of structural, contractile, calcium-handling and metabolic genes (e.g., MYBPC2, MYL3, MYLK2, CACNA2D3, CACNA2D4) and marked upregulation of inflammatory mediators and innate immune receptors (e.g., IL6, IL18, IL1R1, CCR1/2/5, TLR1/2/4/7/9). In contrast, BMD muscle showed partial restoration of these pathways and clustered closer to WT in global expression profiles. Distinct miRNA signatures were observed between DMD and BMD. Differential expression analysis identified 22 upregulated and 12 downregulated miRNAs in DMD versus WT and 36 upregulated and 21 downregulated miRNAs in BMD versus WT. Integration of miRNA and mRNA data yielded extensive regulatory networks (1013 unique pairs for upregulated miRNAs in DMD; 2679 pairs for downregulated miRNAs in BMD). Two condition-specific miRNAs emerged as strong biomarker candidates: ssc-miR-296-3p (upregulated exclusively in DMD, targeting 228 genes enriched in muscle structure and fatty acid metabolism) and ssc-miR-423-5p (elevated specifically in BMD, targeting 67 genes involved in calcium signalling and tissue development). Several dysregulated miRNAs, including miR-199a-5p and miR-199b, overlapped with those reported in human DMD and other muscular dystrophies. CONCLUSIONS: Exon 51 skipping in the DMDΔ52 background partially restores key transcriptional programmes in skeletal muscle but does not fully normalize them to WT patterns. The identification of condition-specific miRNAs highlights post-transcriptional regulatory differences between DMD and BMD, positioning them as promising biomarkers and therapeutic targets. These findings underscore the translational value of porcine dystrophinopathy models for mechanistic studies and preclinical evaluation of RNA-targeted interventions.

Animals↗

PubMed2025

Optimized genomic editing of a common Duchenne muscular dystrophy mutation in patient-derived muscle cells and a new humanized mouse model.

Duchenne muscular dystrophy (DMD) is a fatal X-linked, recessive disease caused by mutations in the DMD gene encoding dystrophin, a membrane-associated protein necessary for maintaining muscle structure and function. One of the common DMD mutations is the deletion of exon 52 (Δ52), which introduces a premature stop codon in exon 53, preventing the expression of functional dystrophin protein. Patients with this mutation could benefit from skipping or reframing exon 53 to restore the dystrophin open reading frame. In this study, we investigated the efficacy of single-cut CRISPR gene editing with Staphylococcus pyogenes Cas9 (SpCas9)-LRVQR to restore dystrophin expression in patient-derived induced pluripotent stem cells (iPSCs) and a newly generated humanized DMD mouse model. We compared two injection routes for adeno-associated virus (AAV) serotype 9 to deliver gene-editing components to neonatal mice: intraperitoneal (IP) and facial vein (FV) injection. We observed efficient restoration of dystrophin protein expression across multiple skeletal muscle groups and the heart. The AAV9-mediated CRISPR single-cut approach ameliorated key DMD hallmarks, including histopathological phenotypes, impaired grip strength, and elevated serum creatine kinase levels. Our optimized strategies for dystrophin restoration in humanized DMD mice with exon 52 deletion represent a promising treatment for DMD.

AAV↗

PubMed2023

Single-swap editing for the correction of common Duchenne muscular dystrophy mutations.

Duchenne muscular dystrophy (DMD) is a fatal X-linked recessive disease of progressive muscle weakness and wasting caused by the absence of dystrophin protein. Current gene therapy approaches using antisense oligonucleotides require lifelong dosing and have limited efficacy in restoring dystrophin production. A gene editing approach could permanently correct the genome and restore dystrophin protein expression. Here, we describe single-swap editing, in which an adenine base editor edits a single base pair at a splice donor site or splice acceptor site to enable exon skipping or reframing. In human induced pluripotent stem cell-derived cardiomyocytes, we demonstrate that single-swap editing can enable beneficial exon skipping or reframing for the three most therapeutically relevant exons-DMD exons 45, 51, and 53-which could be beneficial for 30% of all DMD patients. Furthermore, an adeno-associated virus delivery method for base editing components can efficiently restore dystrophin production locally and systemically in skeletal and cardiac muscles of a DMD mouse model containing a deletion of Dmd exon 44. Our studies demonstrate single-swap editing as a potential gene editing therapy for common DMD mutations.

AAV↗

PubMed2024

Identifying inversions with breakpoints in the Dystrophin gene through long-read sequencing: report of two cases.

BACKGROUND: Duchenne Muscular Dystrophy (DMD) is an X-linked disorder caused by mutations in the DMD gene, with large deletions being the most common type of mutation. Inversions involving the DMD gene are a less frequent cause of the disorder, largely because they often evade detection by standard diagnostic methods such as multiplex ligation probe amplification (MLPA) and whole exome sequencing (WES). CASE PRESENTATION: Our research identified two intrachromosomal inversions involving the dystrophin gene in two unrelated families through Long-read sequencing (LRS). These variants were subsequently confirmed via Sanger sequencing. The first case involved a pericentric inversion extending from DMD intron 47 to Xq27.3. The second case featured a paracentric inversion between DMD intron 42 and Xp21.1, inherited from the mother. In both cases, simple repeat sequences (SRS) were present at the breakpoints of these inversions. CONCLUSIONS: Our findings demonstrate that LRS is an effective tool for detecting atypical mutations. The identification of SRS at the breakpoints in DMD patients enhances our understanding of the mechanisms underlying structural variations, thereby facilitating the exploration of potential treatments.

Humans↗

PubMed2024

Progressive cardiomyopathy with intercalated disc disorganization in a rat model of Becker dystrophy.

Becker muscular dystrophy (BMD) is an X-linked disorder due to in-frame mutations in the DMD gene, leading to a less abundant and truncated dystrophin. BMD is less common and severe than Duchenne muscular dystrophy (DMD) as well as less investigated. To accelerate the search for innovative treatments, we developed a rat model of BMD by deleting the exons 45-47 of the Dmd gene. Here, we report a functional and histopathological evaluation of these rats during their first year of life, compared to DMD and control littermates. BMD rats exhibit moderate damage to locomotor and diaphragmatic muscles but suffer from a progressive cardiomyopathy. Single nuclei RNA-seq analysis of cardiac samples revealed shared transcriptomic abnormalities in BMD and DMD rats and highlighted an altered end-addressing of TMEM65 and Connexin-43 at the intercalated disc, along with electrocardiographic abnormalities. Our study documents the natural history of a translational preclinical model of BMD and reports a cellular mechanism for the cardiac dysfunction in BMD and DMD offering opportunities to further investigate the organization role of dystrophin in intercellular communication.

Animals↗

PubMed2024

Exome sequencing reveals neurodevelopmental genes in simplex consanguineous Iranian families with syndromic autism.

BACKGROUND AND OBJECTIVE: Autosomal recessive genetic disorders pose significant health challenges in regions where consanguineous marriages are prevalent. The utilization of exome sequencing as a frequently employed methodology has enabled a clear delineation of diagnostic efficacy and mode of inheritance within multiplex consanguineous families. However, these aspects remain less elucidated within simplex families. METHODS: In this study involving 12 unrelated simplex Iranian families presenting syndromic autism, we conducted singleton exome sequencing. The identified genetic variants were validated using Sanger sequencing, and for the missense variants in FOXG1 and DMD, 3D protein structure modeling was carried out to substantiate their pathogenicity. To examine the expression patterns of the candidate genes in the fetal brain, adult brain, and muscle, RT-qPCR was employed. RESULTS: In four families, we detected an autosomal dominant gene (FOXG1), an autosomal recessive gene (CHKB), and two X-linked autism genes (IQSEC2 and DMD), indicating diverse inheritance patterns. In the remaining eight families, we were unable to identify any disease-associated genes. As a result, our variant detection rate stood at 33.3% (4/12), surpassing rates reported in similar studies of smaller cohorts. Among the four newly identified coding variants, three are de novo (heterozygous variant p.Trp546Ter in IQSEC2, heterozygous variant p.Ala188Glu in FOXG1, and hemizygous variant p.Leu211Met in DMD), while the homozygous variant p.Glu128Ter in CHKB was inherited from both healthy heterozygous parents. 3D protein structure modeling was carried out for the missense variants in FOXG1 and DMD, which predicted steric hindrance and spatial inhibition, respectively, supporting the pathogenicity of these human mutants. Additionally, the nonsense variant in CHKB is anticipated to influence its dimerization - crucial for choline kinase function - and the nonsense variant in IQSEC2 is predicted to eliminate three functional domains. Consequently, these distinct variants found in four unrelated individuals with autism are likely indicative of loss-of-function mutations. CONCLUSIONS: In our two syndromic autism families, we discovered variants in two muscular dystrophy genes, DMD and CHKB. Given that DMD and CHKB are recognized for their participation in the non-cognitive manifestations of muscular dystrophy, it indicates that some genes transcend the boundary of apparently unrelated clinical categories, thereby establishing a novel connection between ASD and muscular dystrophy. Our findings also shed light on the complex inheritance patterns observed in Iranian consanguineous simplex families and emphasize the connection between autism spectrum disorder and muscular dystrophy. This underscores a likely genetic convergence between neurodevelopmental and neuromuscular disorders.

Humans↗

PubMed2026

Duchenne muscular dystrophy: from gene to gene-ius therapies.

Duchenne muscular dystrophy (DMD) is a severe X-linked neuromuscular disorder caused by mutations in the dystrophin gene that result in the absence of functional dystrophin, leading to progressive muscle degeneration, loss of ambulation, respiratory failure, cardiomyopathy, and premature mortality. Despite advances in multidisciplinary supportive care, DMD remains an incurable disease associated with substantial physical, psychosocial, and economic burdens. The monogenic nature of DMD and its well-defined molecular pathogenesis have made it a prime target for the development of precision therapies aimed at restoring dystrophin expression or modifying disease progression. This review provides an overview of the genetic and molecular mechanisms underlying DMD, summarizes its clinical manifestations and natural history, and discusses current standards of care. It further examines recent advances in disease-modifying therapeutic strategies, including exon-skipping antisense oligonucleotides, nonsense mutation readthrough agents, adeno-associated virus (AAV)-mediated micro-dystrophin gene replacement, and emerging genome-editing technologies such as CRISPR/Cas9. The review also highlights the limitations of existing treatments, including mutation specificity, variable efficacy, immune-related challenges, and uncertainties regarding long-term durability and safety. Finally, it considers future directions in therapeutic development, emphasizing the need for combination approaches, improved delivery systems, and next-generation gene-editing platforms to achieve more effective and lasting clinical outcomes. Collectively, these advances represent a paradigm shift in DMD management and offer renewed hope for improving survival and quality of life for affected individuals.

Humans↗

PubMed2025

Spatiotemporal diversity in molecular and functional abnormalities in the mdx dystrophic brain.

Duchenne muscular dystrophy (DMD) is characterized by progressive muscle degeneration and neuropsychiatric abnormalities. Loss of full-length dystrophins is both necessary and sufficient to initiate DMD. These isoforms are expressed in the hippocampus, cerebral cortex (Dp427c), and cerebellar Purkinje cells (Dp427p). However, our understanding of the consequences of their absence, which is crucial for developing targeted interventions, remains inadequate. We combined RNA sequencing with genome-scale metabolic modelling (GSMM), immunodetection, and mitochondrial assays to investigate dystrophic alterations in the brains of the mdx mouse model of DMD. The cerebra and cerebella were analysed separately to discern the roles of Dp427c and Dp427p, respectively. Investigating these regions at 10 days (10d) and 10 weeks (10w) followed the evolution of abnormalities from development to early adulthood. These time points also encompass periods before onset and during muscle inflammation, enabling assessment of the potential damage caused by inflammatory mediators crossing the dystrophic blood-brain barrier. For the first time, we demonstrated that transcriptomic and functional dystrophic alterations are unique to the cerebra and cerebella and vary substantially between 10d and 10w. The common anomalies involved altered numbers of retained introns and spliced exons across mdx transcripts, corresponding with alterations in the mRNA processing pathways. Abnormalities in the cerebra were significantly more pronounced in younger mice. The top enriched pathways included those related to metabolism, mRNA processing, and neuronal development. GSMM indicated dysregulation of glucose metabolism, which corresponded with GLUT1 protein downregulation. The cerebellar dystrophic transcriptome, while significantly altered, showed an opposite trajectory to that of the cerebra, with few changes identified at 10 days. These late defects are specific and indicate an impact on the functional maturation of the cerebella that occurs postnatally. Although no classical neuroinflammation markers or microglial activation were detected at 10 weeks, specific differences indicate that inflammation impacts DMD brains. Importantly, some dystrophic alterations occur late and may therefore be amenable to therapeutic intervention, offering potential avenues for mitigating DMD-related neuropsychiatric defects.

Animals↗

PubMed2026

Improving survival in Duchenne muscular dystrophy across eras: a systematic review and cumulative meta-analysis.

BACKGROUND: Duchenne muscular dystrophy (DMD) was historically associated with death in the late teens or early twenties, mainly from respiratory failure. Survival has improved substantially with home mechanical ventilation (HMV) and multidisciplinary care, although variability remains. This study evaluated temporal trends in survival in DMD and the impact of HMV. METHODS: A study-level cumulative meta-analysis (PROSPERO CRD420251163011) of studies reporting survival outcomes in patients with DMD was conducted (PubMed 1977 to 13 October 2025). Pooled estimates of median survival were calculated, and random-effects meta-analyses with predefined subgroups (HMV and study period) were performed, alongside meta-regressions. Risk of bias was assessed using the Newcastle-Ottawa Scale. RESULTS: 53 studies (median follow-up 8 years), comprising more than 13,000 patients, of whom 60% received HMV, were included. Median survival differed substantially between ventilated (29 years, 95%CI 27 to 31) and non-ventilated (19 years, 95%CI 18 to 20) patients. Survival improved progressively over time in both groups. Glucocorticoid therapy was not associated with improved survival (p=0.45), whereas treatment with heart failure medications, including renin-angiotensin system inhibitors (p=0.002) and β-blockers (p=0.02), was associated with longer survival. The predominance of mortality shifted from respiratory to cardiac causes, while enhanced cardiac management was associated with a growing contribution of other causes of death. CONCLUSION: Survival in DMD has increased substantially over time, with median survival now approaching the third decade of life among ventilated patients. The growing contribution of cardiac and other non-respiratory causes of death highlights the importance of long-term multidisciplinary and early cardioprotective intervention. STUDY REGISTRATION: The meta-analysis and systematic review have been registered on PROSPERO (CRD420251163011).

Humans↗

PubMed2026

Integrative multi-omics analysis reveals lipid/metabolite dysregulation and temporal decoupling in disease progression.

Our study presents and applies a metabolomics-driven multi-omics integration strategy to elucidate dynamic pathway interactions during disease progression. We analyzed longitudinal metabolomics datasets from a Duchenne muscular dystrophy (DMD) mouse model (6-30 weeks) and an acute Bothrops asper envenomation model (1-24 h) to contrast chronic versus acute inflammation. In the DMD model, we predicted phased cross-talk between sphingolipid metabolism and neurotrophin signaling: an early proteomic surge followed by lipid-mediated amplification and a late convergence at the protein level. Arginine and proline metabolism exhibited early metabolite accumulation preceding delayed inferred protein changes, consistent with impaired nitric oxide synthesis and argininemia-like effect. We also predicted late-stage activation of the AGE-RAGE pathway in DMD, likely triggered by ceramide buildup, and an autophagy-related lipid metabolic shift at mid-stage. In the envenomation model, tryptophan-kynurenine and nicotinamide pathways for NAD⁺ biosynthesis were rapidly perturbed at the metabolite level (1-3 h) but induced corresponding predicted enzymes only by 24 h. Thyroid hormone signaling showed an early coupling of substrate availability (tyrosine surge at 1 h) with predicted stress-response proteins and a second, delayed wave of inferred transcriptional regulators at 24 h. Acute envenomation also triggered immediate glycine/serine utilization possibly for antioxidant defense and glycerophospholipid breakdown (via phospholipase A₂), whereas chronic DMD showed sustained glycine/serine engagement and inferred, unresolved phospholipid perturbation without protein-level compensation, which may result from chronic oxidative stress. Overall, our integrative analysis revealed time-specific, multi-layer molecular perturbations distinguishing acute toxin injury from chronic muscle degeneration. Key metabolic control points (ceramide accumulation, arginine flux diversion, autophagy-lipid cross-talk, NAD⁺ salvage timing) were identified, highlighting potential targets for stage-specific therapeutic or nutritional interventions.

Animals↗

PubMed2015

Perspective on Adeno-Associated Virus Capsid Modification for Duchenne Muscular Dystrophy Gene Therapy.

Duchenne muscular dystrophy (DMD) is a X-linked, progressive childhood myopathy caused by mutations in the dystrophin gene, one of the largest genes in the genome. It is characterized by skeletal and cardiac muscle degeneration and dysfunction leading to cardiac and/or respiratory failure. Adeno-associated virus (AAV) is a highly promising gene therapy vector. AAV gene therapy has resulted in unprecedented clinical success for treating several inherited diseases. However, AAV gene therapy for DMD remains a significant challenge. Hurdles for AAV-mediated DMD gene therapy include the difficulty to package the full-length dystrophin coding sequence in an AAV vector, the necessity for whole-body gene delivery, the immune response to dystrophin and AAV capsid, and the species-specific barriers to translate from animal models to human patients. Capsid engineering aims at improving viral vector properties by rational design and/or forced evolution. In this review, we discuss how to use the state-of-the-art AAV capsid engineering technologies to overcome hurdles in AAV-based DMD gene therapy.

Animals↗

PubMed2023

Assessment of systemic AAV-microdystrophin gene therapy in the GRMD model of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a progressive muscle wasting disease caused by the absence of dystrophin, a membrane-stabilizing protein encoded by the DMD gene. Although mouse models of DMD provide insight into the potential of a corrective therapy, data from genetically homologous large animals, such as the dystrophin-deficient golden retriever muscular dystrophy (GRMD) model, may more readily translate to humans. To evaluate the clinical translatability of an adeno-associated virus serotype 9 vector (AAV9)-microdystrophin (μDys5) construct, we performed a blinded, placebo-controlled study in which 12 GRMD dogs were divided among four dose groups [control, 1 × 1013 vector genomes per kilogram (vg/kg), 1 × 1014 vg/kg, and 2 × 1014 vg/kg; n = 3 each], treated intravenously at 3 months of age with a canine codon-optimized microdystrophin construct, rAAV9-CK8e-c-μDys5, and followed for 90 days after dosing. All dogs received prednisone (1 milligram/kilogram) for a total of 5 weeks from day -7 through day 28. We observed dose-dependent increases in tissue vector genome copy numbers; μDys5 protein in multiple appendicular muscles, the diaphragm, and heart; limb and respiratory muscle functional improvement; and reduction of histopathologic lesions. As expected, given that a truncated dystrophin protein was generated, phenotypic test results and histopathologic lesions did not fully normalize. All administrations were well tolerated, and adverse events were not seen. These data suggest that systemically administered AAV-microdystrophin may be dosed safely and could provide therapeutic benefit for patients with DMD.

Animals↗

PubMed2025

Proteomics of Duchenne Muscular Dystrophy Patient iPSC-Derived Skeletal Muscle Cells Reveal Differential Expression of Cytoskeletal and Extracellular Matrix Proteins.

Proteomics of dystrophic muscle samples is limited by the amount of protein that can be extracted from patient biopsies. Cells and tissues derived from patient-derived induced pluripotent stem cells (iPSCs) can be an expandable alternative source. We have patterned iPSCs from three Duchenne muscular dystrophy (DMD) patient lines into skeletal muscle cells using a two-dimensional as well as our three-dimensional organoid differentiation system. Probes with sufficient protein amounts could be extracted and prepared for mass spectrometry. In total, 3007 proteins in 2D and 2709 proteins in 3D were detected in DMD patient probes. A total of 83 proteins in 2D and 338 proteins in 3D can be described as differentially expressed between DMD and control patient probes in a post hoc test. We have identified and we propose Myosin-9, Collagen 18A, Tropomyosin 1, BASP1, RUVBL1, and NCAM1 as proteins specifically altered in their expression in DMD for further investigation. Proteomics of skeletal muscle organoids resulted in greater consistency of results between cell lines in comparison to the two-dimensional myogenic differentiation protocol.

Humans↗

PubMed2026

Multiplexed genome editing by CRISPR-Un1Cas12f1 restores dystrophin expression in a mouse model of Duchenne muscular dystrophy.

The compact type V clustered regularly interspaced short palindromic repeats (CRISPR) nuclease Un1Cas12f1 is compatible with adeno-associated virus (AAV)-mediated genome editing, although the protospacer adjacent motif (PAM) requirements and capacity for multiplexed genome editing remain undefined. Here, we show that Un1Cas12f1 exhibits a broad tolerance for non-canonical PAMs, including Y-rich motifs with a preference for TTCR and TCTA PAMs, thereby expanding the genomic targeting range. We further demonstrate that a tandem sgRNA array expressed from a single transcript supports Un1Cas12f1-mediated multiplexed genome editing at up to five distinct genomic loci. Leveraging this multiplexing capability, we achieved targeted excision of the Dmd exon 23 through intramuscular delivery of an all-in-one AAV vector encoding Un1Cas12f1 and a CRISPR array. This treatment restored the disrupted open reading frame and dystrophin expression in a mouse model of Duchenne muscular dystrophy (DMD). Together, these findings establish Un1Cas12f1 as a compact CRISPR system capable of multiplexed genome editing and demonstrate its therapeutic potential for DMD.

Journal Article↗

PubMed2026

A case report of Xp21 contiguous gene deletion syndrome with adrenal crisis and sensorineural hearing loss: clinical highlights and management pitfalls.

OBJECTIVES: To report a rare association of Xp21 contiguous gene deletion syndrome (CGDS) featuring sensorineural hearing loss (SNHL), and to discuss the diagnostic and therapeutic challenges. CASE PRESENTATION: A male infant presented with a salt-wasting adrenal crisis consistent with X-linked adrenal hypoplasia congenita. His follow-up clinical course during childhood revealed global developmental delay and SNHL, the latter of which has been under-reported in the literature for this condition. At five years of age, the development of progressive proximal muscle weakness and markedly elevated creatine phosphokinase levels led to a diagnosis of Duchenne muscular dystrophy (DMD). The patient also exhibited pseudohypertriglyceridemia and elevated urinary glycerol, consistent with glycerol kinase deficiency. While initial exome sequencing failed to detect the genetic abnormality, subsequent chromosomal microarray analysis identified an Xp21 CGDS involving NR0B1, IL1RAPL1, DMD, and GK. Treatment of adrenal insufficiency with fludrocortisone and hydrocortisone was complicated by the higher steroid doses required for the management of DMD, resulting in exogenous Cushing syndrome and associated complications. CONCLUSIONS: This case highlights the necessity of evaluating for Xp21 CGDS in patients presenting with adrenal crisis and emphasizes the importance of multidisciplinary management to optimize outcomes in this complex pediatric endocrine disorder.

Humans↗

PubMed2025

Enhancing AAV9-UFμDys1 Gene Therapy Efficacy Through Immunosuppression in Mice with Pre-Existing Immunity and Enabling Redosing Strategies for Duchenne Muscular Dystrophy.

Significant progress has been made in gene therapy for Duchenne muscular dystrophy (DMD), a severe genetic disorder primarily affecting pediatric patients. However, the immune responses triggered by high-dose systemic delivery of adeno-associated virus (AAV) vectors remain a major challenge. These responses include the generation of long-lasting anti-capsid antibodies and potential immunity against the therapeutic transgene, rendering gene therapy ineffective. In addition, pre-existing anti-AAV antibodies exclude patients from eligibility for treatment. To address these limitations, we have developed an immunosuppression (IMS) strategy aimed at mitigating immune responses to the AAV capsid while enhancing microdystrophin expression. Using an optimized expression cassette (AAV9-UFµDys1) for sustained microdystrophin expression in striated muscle and heart, we observed a 40% improvement in muscle force compared with animals receiving a GFP-encoding control AAV9 vector. In mdx mice, a single-dose IMS regimen significantly increased microdystrophin expression in cardiac and skeletal tissues and repeat dosing further enhanced expression, an effect not observed in non-IMS-treated mdx mice. To model pre-existing immunity, we immune-challenged wild-type mice with empty AAV9 capsids and tracked antibody responses over time. The IMS regimen effectively reduced total anti-AAV antibody levels and increased microdystrophin expression in UFµDys1-treated mice. These findings highlight the potential of IMS to minimize immune barriers, facilitate repeat AAV administration, and expand the therapeutic window for DMD gene therapy. Our results support the further development of AAV-mediated approaches using either microdystrophin-expressing vectors or next-generation systems delivering full-length or near-full-length dystrophin.

Animals↗

PubMed2012

MRI roadmap-guided transendocardial delivery of exon-skipping recombinant adeno-associated virus restores dystrophin expression in a canine model of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) cardiomyopathy patients currently have no therapeutic options. We evaluated catheter-based transendocardial delivery of a recombinant adeno-associated virus (rAAV) expressing a small nuclear U7 RNA (U7smOPT) complementary to specific cis-acting splicing signals. Eliminating specific exons restores the open reading frame resulting in translation of truncated dystrophin protein. To test this approach in a clinically relevant DMD model, golden retriever muscular dystrophy (GRMD) dogs received serotype 6 rAAV-U7smOPT via the intracoronary or transendocardial route. Transendocardial injections were administered with an injection-tipped catheter and fluoroscopic guidance using X-ray fused with magnetic resonance imaging (XFM) roadmaps. Three months after treatment, tissues were analyzed for DNA, RNA, dystrophin protein, and histology. Whereas intracoronary delivery did not result in effective transduction, transendocardial injections, XFM guidance, enabled 30±10 non-overlapping injections per animal. Vector DNA was detectable in all samples tested and ranged from <1 to >3000 vector genome copies per cell. RNA analysis, western blot analysis, and immunohistology demonstrated extensive expression of skipped RNA and dystrophin protein in the treated myocardium. Left ventricular function remained unchanged over a 3-month follow-up. These results demonstrated that effective transendocardial delivery of rAAV-U7smOPT was achieved using XFM. This approach restores an open reading frame for dystrophin in affected dogs and has potential clinical utility.

Animals↗