Latent factors underlying the symptoms of adult-onset myotonic dystrophy type 1 during the clinical course.

BACKGROUND: Myotonic dystrophy type 1 (DM1) is a multisystem genetic disorder that classically presents with symptoms associated with myotonia, early onset cataracts, and muscular weakness, although the presentation and pattern of disease progression is quite varied. Presenting symptoms are well documented among adults with DM1. However, less is known about the co-occurrence of symptoms over time. We aimed to use factor analysis to explore the correlation pattern of signs and symptoms (S/S) that emerged during the clinical course. RESULTS: Clinical records of 228 individuals with adult onset DM1 were abstracted using the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet) from a six-site cohort in the United States during an eight-year study period. Factor analysis was used to group the correlated S/S into latent factors. Three factors were identified. Group 1: 'Facial Weakness/Myotonia' includes the two most common S/S, as indicated by its name. Group 2: 'Skeletal Muscle Weakness' includes eight muscular S/S and is more frequently reported by males and those with older age at onset. Group 3: 'Gastrointestinal distress/Sleepiness' includes four non-muscular S/S and hand stiffness. The abstracted medical records reported that over 63% of individuals had S/S from all three groups. Associations of covariates with factor scores were also examined using linear regression. CTG repeat length was significantly positively associated with higher factor scores for all three factors. CONCLUSIONS: This study identified three latent factors of S/S which accumulated during the clinical course of adult onset DM1.

Temporal variation in p38-mediated regulation of DUX4 in facioscapulohumeral muscular dystrophy.

Facioscapulohumeral muscular dystrophy (FSHD) is a degenerative muscle disease caused by loss of epigenetic silencing and ectopic reactivation of the embryonic double homeobox protein 4 gene (DUX4) in skeletal muscle. The p38 MAP kinase inhibitor losmapimod is currently being tested in FSHD clinical trials due to the finding that p38 inhibition suppresses DUX4 expression in preclinical models. However, the role of p38 in regulating DUX4 at different myogenic stages has not been investigated. We used genetic and pharmacologic tools in FSHD patient-derived myoblasts/myocytes to explore the temporal role of p38 in differentiation-induced DUX4 expression. Deletion of MAPK14/11 or inhibition of p38α/ß caused a significant reduction in early differentiation-dependent increases in DUX4 and DUX4 target gene expression. However, in MAPK14/11 knockout cells, there remains a differentiation-associated increase in DUX4 and DUX4 target gene expression later in differentiation. Furthermore, pharmacologic inhibition of p38α/ß only partially decreased DUX4 and DUX4 target gene expression in late differentiating myotubes. In xenograft studies, p38α/ß inhibition by losmapimod failed to suppress DUX4 target gene expression in late FSHD xenografts. Our results show that while p38 is critical for DUX4 expression during early myogenesis, later in myogenesis a significant level of DUX4 expression is independent of p38α/ß activity.

Successful treatment of nail psoriasis with topical roflumilast: A case report.

Nail psoriasis occurs in approximately half of all cases of plaque psoriasis and manifests with onychodystrophy, which includes morphological features of onycholysis, subungual hyperkeratosis, oil drop sign, pitting, splinter hemorrhages, leukonychia, and crumbling of the nails. Nail psoriasis can have a significant adverse impact on quality of life. However, nail psoriasis is often refractory to both local and systemic therapies, making it challenging to treat. Topical and oral phosphodiesterase-4 inhibitors have been successfully used to treat multiple different subtypes of psoriasis. Topical roflumilast, a phosphodiesterase-4 inhibitor cream, has recently received United States Food and Drug Administration and Health Canada approval for the treatment of plaque psoriasis. In this case report, a 25-year-old female with a 20-year history of nail psoriasis achieved complete resolution of her onychodystrophy after 5 months of daily application of topical roflumilast, without experiencing any side effects. This case report suggests that topical roflumilast may be a useful and well-tolerated therapy for psoriatic nails.

Yearly motor function changes in patients with Duchenne muscular dystrophy, including a COVID-19 behavioral restriction period.

[Purpose] This study aimed to assess the motor function status of ambulatory patients with Duchenne muscular dystrophy in 2020, which included a 3-month period of behavioral restriction due to the coronavirus disease of 2019 (COVID-19) pandemic, in comparison to the previous 2 years. [Participants and Methods] A retrospective analysis was conducted on 12 patients (children with mean age: 9.58 ± 3.43 years in 2020). Parameters such as lower leg maximum circumference, 10-m running time, rising-from-the-floor time, ankle joint range-of-motion, 6-min walk distance, and North Star Ambulatory Assessment score were evaluated. [Results] Significant increases in the maximum right thigh circumference and prolonged 10-m running time were observed in 2020. Interestingly, an unexpected improvement in ankle dorsiflexion angle was noted in both ankles. No other statistically significant differences were observed among the assessed time points. [Conclusion] These findings highlight the critical importance of continuous exercise and rehabilitation for ambulatory children with Duchenne muscular dystrophy, emphasizing the potential of rehabilitation to mitigate and restore the transient motor function deterioration observed during periods of behavioral restrictions.

Direct delivery of Cas9 or base editor protein and guide RNA complex enables genome editing in the retina.

Genome editing by CRISPR-Cas holds promise for the treatment of retinal dystrophies. For therapeutic gene editing, transient delivery of CRISPR-Cas9 is preferable to viral delivery which leads to long-term expression with potential adverse consequences. Cas9 protein and its guide RNA, delivered as ribonucleoprotein (RNP) complexes, have been successfully delivered into the retinal pigment epithelium in vivo. However, the delivery into photoreceptors, the primary focus in retinal dystrophies, has not been achieved. Here, we investigate the feasibility of direct RNP delivery into photoreceptors and retinal pigment epithelium cells. We demonstrate that Cas9 or adenine-base editors complexed with guide RNA, can enter retinal cells without the addition of any carrier compounds. Once in the retinal cells, editing rates vary based on the efficacy of the guide RNA and the specific location edited within the genes. Cas9 RNP delivery at high concentrations, however, leads to outer retinal toxicity. This underscores the importance of improving delivery efficiency for potential therapeutic applications in the future.

Clinical and Molecular Profiles of a Cohort of Egyptian Patients with Collagen VI-Related Dystrophy.

Collagen VI-related dystrophies (COL6-RD) display a wide spectrum of disease severity and genetic variability ranging from mild Bethlem myopathy (BM) to severe Ullrich congenital muscular dystrophy (UCMD) and the intermediate severities in between with dual modes of inheritance, dominant and recessive. In the current study, next-generation sequencing demonstrated potential variants in the genes coding for the three alpha chains of collagen VI (COL6A1, COL6A2, or COL6A3) in a cohort of Egyptian patients with progressive muscle weakness (n = 23). Based on the age of disease onset and the patient clinical course, subjects were diagnosed as follows: 12 with UCMD, 8 with BM, and 3 with intermediate disease form. Fourteen pathogenic variants, including 5 novel alterations, were reported in the enrolled subjects. They included 3 missense, 3 frameshift, and 6 splicing variants in 4, 3, and 6 families, respectively. In addition, a nonsense variant in a single family and an inframe variant in 3 different families were also detected. Recessive and dominant modes of inheritance were recorded in 9 and 8 families, respectively. According to ACMG guidelines, variants were classified as pathogenic (n = 7), likely pathogenic (n = 4), or VUS (n = 3) with significant pathogenic potential. To our knowledge, the study provided the first report of the clinical and genetic findings of a cohort of Egyptian patients with collagen VI deficiency. Inter- and intra-familial clinical variability was evident among the study cohort.

Deletion of exons 45 to 55 in the DMD gene: from the therapeutic perspective to the in vitro model.

BACKGROUND: Gene editing therapies in development for correcting out-of-frame DMD mutations in Duchenne muscular dystrophy aim to replicate benign spontaneous deletions. Deletion of 45-55 DMD exons (del45-55) was described in asymptomatic subjects, but recently serious skeletal and cardiac complications have been reported. Uncovering why a single mutation like del45-55 is able to induce diverse phenotypes and grades of severity may impact the strategies of emerging therapies. Cellular models are essential for this purpose, but their availability is compromised by scarce muscle biopsies. METHODS: We introduced, as a proof-of-concept, using CRISPR-Cas9 edition, a del45-55 mimicking the intronic breakpoints harboured by a subset of patients of this form of dystrophinopathy (designing specific gRNAs), into a Duchenne patient's cell line. The edited cell line was characterized evaluating the dystrophin expression and the myogenic status. RESULTS: Dystrophin expression was restored, and the myogenic defects were ameliorated in the edited myoblasts harbouring a specific del45-55. Besides confirming the potential of CRISPR-Cas9 to create tailored mutations (despite the low cleavage efficiency of our gRNAs) as a useful approach to generate in vitro models, we also generated an immortalized myoblast line derived from a patient with a specific del45-55. CONCLUSIONS: Overall, we provide helpful resources to deepen into unknown factors responsible for DMD-pathophysiology.

A novel RPE65 variant p.(Ala391Asp) in Leber congenital amaurosis: a case report and literature review in Japan.

Introduction: In Japan, inherited retinal dystrophy caused by biallelic variants of the RPE65 gene is exceedingly rare. The purpose of this study was to describe a Japanese male patient with a novel variant in RPE65 associated with Leber congenital amaurosis (LCA). Case report: The patient, diagnosed with LCA, exhibited infantile nystagmus and reported experiencing night blindness since early childhood. At 27 years of age, the patient underwent an ophthalmologically evaluation. Corrected visual acuity was Snellen equivalent 20/133 in the right eye and Snellen equivalent 20/100 in the left eye. Fundus examination revealed alterations in the retinal pigment epithelium characterized by hypopigmentation and narrowing of retinal vessels. Fundus autofluorescence imaging demonstrated a generally diminished autofluorescent signal. Full-field electroretinography identified a generalized dysfunction of both rod and cone systems in each eye. Whole exome sequencing identified a novel missense variant in RPE65 (NM_000329.3): c.1172C > A p.(Ala391Asp), which was classified as pathogenic, as well as a recurrent variant p.(Arg515Trp). Conclusion: This study provides valuable insights into the genotype-phenotype correlation of RPE65-associated LCA in Japanese patients, with critical implications for enhanced diagnostic accuracy and informed therapeutic decisions.

Human iPSC-based disease modeling studies identify a common mechanistic defect and potential therapies for AMD and related macular dystrophies.

Age-related macular degeneration (AMD) and related macular dystrophies (MDs) primarily affect the retinal pigment epithelium (RPE) in the eye. A hallmark of AMD/MDs that drives later-stage pathologies is drusen. Drusen are sub-RPE lipid-protein-rich extracellular deposits, but how drusen forms and accumulates is not known. We utilized human induced pluripotent stem cell (iPSC)-derived RPE from patients with AMD and three distinct MDs to demonstrate that reduced activity of RPE-secreted matrix metalloproteinase 2 (MMP2) contributes to drusen in multiple maculopathies in a genotype-agnostic manner by instigating sterile inflammation and impaired lipid homeostasis via damage-associated molecular pattern molecule (DAMP)-mediated activation of receptor for advanced glycation end-products (RAGE) and increased secretory phospholipase 2-IIA (sPLA2-IIA) levels. Therapeutically, RPE-specific MMP2 supplementation, RAGE-antagonistic peptide, and a small molecule inhibitor of sPLA2-IIA ameliorated drusen accumulation in AMD/MD iPSC-RPE. Ultimately, this study defines a causal role of the MMP2-DAMP-RAGE-sPLA2-IIA axis in AMD/MDs.

Transcriptional changes of genes encoding sarcoplasmic reticulum calcium binding and up-taking proteins in normal and Duchenne muscular dystrophy dogs.

BACKGROUND: Cytosolic calcium overload contributes to muscle degradation in Duchenne muscular dystrophy (DMD). The sarcoplasmic reticulum (SR) is the primary calcium storage organelle in muscle. The sarco-endoplasmic reticulum ATPase (SERCA) pumps cytosolic calcium to the SR during muscle relaxation. Calcium is kept in the SR by calcium-binding proteins. METHODS: Given the importance of the canine DMD model in translational studies, we examined transcriptional changes of SERCA (SERCA1 and SERCA2a), SERCA regulators (phospholamban, sarcolipin, myoregulin, and dwarf open reading frame), and SR calcium-binding proteins (calreticulin, calsequestrin 1, calsequestrin 2, and sarcalumenin) in skeletal muscle (diaphragm and extensor carpi ulnaris) and heart (left ventricle) in normal and affected male dogs by droplet digital PCR before the onset (≤ 2-m-old), at the active stage (8 to 16-m-old), and at the terminal stage (30 to 50-m-old) of the disease. Since many of these proteins are expressed in a fiber type-specific manner, we also evaluated fiber type composition in skeletal muscle. RESULTS: In affected dog skeletal muscle, SERCA and its regulators were down-regulated at the active stage, but calcium-binding proteins (except for calsequestrin 1) were upregulated at the terminal stage. Surprisingly, nominal differences were detected in the heart. We also examined whether there exists sex-biased expression in 8 to 16-m-old dogs. Multiple transcripts were significantly downregulated in the heart and extensor carpi ulnaris muscle of female dogs. In fiber type analysis, we found significantly more type I fiber in the diaphragm of 8 to 16-m-old affected dogs, and significantly more type II fibers in the extensor carpi ulnaris of 30 to 50-m-old affected dogs. However, no difference was detected between male and female dogs. CONCLUSIONS: Our study adds new knowledge to the understanding of muscle calcium regulation in normal and dystrophic canines.

Microperimetry Sensitivity Correlates to Structural Macular Changes in Adolescents with Achromatopsia Unlike Other Visual Function Tests.

Objectives: Achromatopsia (ACHM) is a rare autosomal, recessively inherited disease that is characterized by cone dysfunction, for which several gene therapies are currently on trial. The aim of this study was to find correlations between the morphological macular changes identified using optical coherence tomography (OCT) and some visual functional parameters. Visual acuity (VA), contrast sensitivity (CS), and macular sensitivity obtained by means of microperimetry were assessed. Methods: Adolescents with ACHM underwent macular microperimetry (S-MAIA device) in mesopic condition, macular OCT, best corrected visual acuity (BCVA), low luminance visual acuity (LLVA), near vision acuity (NVA), and CS measurement. Results: Eight patients (15 eyes) with ACHM were analyzed. The mean age was 17 ± 2.7 years, and genetic variants involved the CNGA3 gene (37.5%) and CNGB3 gene (62.5%). OCT staging significantly correlated with microperimetry sensitivity parameters, namely the sensitivity of the central foveal point (p = 0.0286) and of the first and second perifoveal rings (p = 0.0008 and p = 0.0014, respectively). No correlations were found between OCT staging and VA measurements, nor with CS value. Conclusions: Among the extensive evaluated visual function tests, only microperimetry sensitivity showed a correlation with morphological macular changes identified at OCT. Microperimetry sensitivity may thus represent a useful visual function tool in natural ACHM history studies considering the upcoming research on gene therapies for the treatment of ACHM.

Molecular Study of the Fukutin-Related Protein (FKRP) Gene in Patients from Southern Italy with Duchenne/Becker-like Phenotype.

Pathogenic variants localized in the gene coding for the Fukutin-Related Protein (FKRP) are responsible for Limb-Girdle Muscular Dystrophy type 9 (LGMDR9), Congenital Muscular Dystrophies type 1C (MDC1C), Walker-Warburg Syndrome (WWS), and Muscle-Eye-Brain diseases (MEBs). LGMDR9 is the fourth most common hereditary Limb Girdle Muscular Dystrophy in Italy. LGMDR9 patients with severe disease show an overlapping Duchenne/Becker phenotype and may have secondary dystrophin reduction on muscle biopsy. We conducted a molecular analysis of the FKRP gene by direct sequencing in 153 patients from Southern Italy (Calabria) with Duchenne/Becker-like phenotypes without confirmed genetic diagnosis. Mutational screening of the patients (112 men and 41 women, aged between 5 and 84 years), revealed pathogenic variants in 16 subjects. The most frequent variants identified were c.427C > A, p.R143S, and c.826C > A, p.L276I (NM_024301.5). The results obtained show that the Duchenne/Becker-like phenotype is frequently determined by mutations in the FKRP gene in our cohort and highlight the importance of considering LGMDR9 in the differential diagnosis of dystrophinopathies in Calabria. Finally, this study, which, to our knowledge, is the first conducted on Calabrian subjects, will contribute to the rapid identification and management of LGMDR9 patients.

Macrophages in the Context of Muscle Regeneration and Duchenne Muscular Dystrophy.

Macrophages are essential to muscle regeneration, as they regulate inflammation, carry out phagocytosis, and facilitate tissue repair. These cells exhibit phenotypic switching from pro-inflammatory (M1) to anti-inflammatory (M2) states during muscle repair, influencing myoblast proliferation, differentiation, and myofiber formation. In Duchenne Muscular Dystrophy (DMD), asynchronous muscle injuries disrupt the normal temporal stages of regeneration, leading to fibrosis and failed regeneration. Altered macrophage activity is associated with DMD progression and physiopathology. Gaining insight into the intricate relationship between macrophages and muscle cells is crucial for creating effective therapies aimed at treating this muscle disorder. This review explores the dynamic functions of macrophages in muscle regeneration and their implications in DMD.

An Autopsy Case of Myotonic Dystrophy Type 1 With Pancreatic Intraductal Papillary Mucinous Neoplasm.

Here, we present an autopsy case of long-standing myotonic dystrophy type 1 (DM1) in a patient who developed a pancreatic intraductal papillary mucinous neoplasm (IPMN). DM1 is a progressive genetic disorder that affects multiple organs, including the respiratory muscles. Several nationwide registry-based cohort studies have suggested that patients with DM1 have an increased risk of developing pancreatic cancers such as pancreatic ductal adenocarcinoma (PDAC). Pancreatic IPMNs are thought to progress from benign neoplasms to invasive cancers, and surgical specimens are usually required for the pathological diagnosis of pancreatic IPMNs. Although certain risk factors for developing pancreatic IPMNs reportedly overlap with those for PDAC, few cases of DM1 with pancreatic IPMNs have been reported. This is partly because pancreatectomy is associated with relatively high morbidity and mortality rates and few patients with DM1 who are suspected of having pancreatic IPMNs are candidates for surgical resection. Therefore, cases of DM1 with histopathologically diagnosed pancreatic IPMNs are rare, and the accumulation of such cases is important for understanding the association between DM1 and pancreatic IPMNs.

Calcium handling abnormalities increase arrhythmia susceptibility in DMSXL myotonic dystrophy type 1 mice.

BACKGROUND: Myotonic dystrophy type 1 (DM1) is a multiorgan disorder with significant cardiac involvement. ECG abnormalities, including arrhythmias, occur in 80 % of DM1 patients and are the second-most common cause of death after respiratory complications; however, the mechanisms underlying the arrhythmogenesis remain unclear. The objective of this study was to investigate the basis of the electrophysiological abnormalities in DM1 using the DMSXL mouse model. METHODS: ECG parameters were evaluated at baseline and post flecainide challenge. Calcium transient and action potential parameters were evaluated in Langendorff-perfused hearts using fluorescence optical mapping. Calcium transient/sparks were evaluated in ventricular myocytes via confocal microscopy. Protein and mRNA levels for calcium handling proteins were evaluated using western blot and RT-qPCR, respectively. RESULTS: DMSXL mice showed arrhythmic events on ECG including premature ventricular contractions and sinus block. DMSXL mice showed increased calcium transient time to peak without any change to voltage parameters. Calcium alternans and both sustained and non-sustained ventricular tachyarrhythmias were readily inducible in DMSXL mice. The confocal experiments also showed calcium transient alternans and increased frequency of calcium sparks in DMSXL cardiomyocytes. These calcium abnormalities were correlated with increased RyR2 phosphorylation without changes to the other calcium handling proteins. CONCLUSIONS: The DMSXL mouse model of DM1 exhibited enhanced arrhythmogenicity associated with abnormal intracellular calcium handling due to hyperphosphorylation of RyR2, pointing to RyR2 as a potential new therapeutic target in DM1 treatment.

Cerebellar dysfunction in the mdx mouse model of Duchenne muscular dystrophy: An electrophysiological and behavioural study.

Patients with Duchenne muscular dystrophy (DMD) commonly show specific cognitive deficits in addition to a severe muscle impairment caused by the absence of dystrophin expression in skeletal muscle. These cognitive deficits have been related to the absence of dystrophin in specific regions of the central nervous system, notably cerebellar Purkinje cells (PCs). Dystrophin has recently been involved in GABAA receptors clustering at postsynaptic densities, and its absence, by disrupting this clustering, leads to decreased inhibitory input to PC. We performed an in vivo electrophysiological study of the dystrophin-deficient muscular dystrophy X-linked (mdx) mouse model of DMD to compare PC firing and local field potential (LFP) in alert mdx and control C57Bl/10 mice. We found that the absence of dystrophin is associated with altered PC firing and the emergence of fast (~160-200 Hz) LFP oscillations in the cerebellar cortex of alert mdx mice. These abnormalities were not related to the disrupted expression of calcium-binding proteins in cerebellar PC. We also demonstrate that cerebellar long-term depression is altered in alert mdx mice. Finally, mdx mice displayed a force weakness, mild impairment of motor coordination and balance during behavioural tests. These findings demonstrate the existence of cerebellar dysfunction in mdx mice. A similar cerebellar dysfunction may contribute to the cognitive deficits observed in patients with DMD.

Small Molecule Screening Identifies HSP90 as a Modifier of RNA Foci in Myotonic Dystrophy Type 1.

Myotonic dystrophy type 1 (DM1) is a multisystemic disorder caused by a CTG triplet repeat expansion within the 3' untranslated region of the DMPK gene. Expression of the expanded allele generates RNA containing long tracts of CUG repeats (CUGexp RNA) that form hairpin structures and accumulate in nuclear RNA foci; however, the factors that control DMPK expression and the formation of CUGexp RNA foci remain largely unknown. We performed an unbiased small molecule screen in an immortalized human DM1 skeletal muscle myoblast cell line and identified HSP90 as a modifier of endogenous RNA foci. Small molecule inhibition of HSP90 leads to enhancement of RNA foci and upregulation of DMPK mRNA levels. Knockdown and overexpression of HSP90 in undifferentiated DM1 myoblasts validated the impact of HSP90 with upregulation and downregulation of DMPK mRNA, respectively. Furthermore, we identified p-STAT3 as a downstream mediator of HSP90 impacting levels of DMPK mRNA and RNA foci. Interestingly, differentiated cells exhibited an opposite effect of HSP90 inhibition displaying downregulation of DMPK mRNA through a mechanism independent of p-STAT3 involvement. This study has revealed a novel mediator for DMPK mRNA and foci regulation in DM1 cells with the potential to identify targets for future therapeutic intervention.

Identification of Pathogenic Copy Number Variants in Mexican Patients With Inherited Retinal Dystrophies Applying an Exome Sequencing Data-Based Read-Depth Approach.

BACKGROUND: Retinal dystrophies (RDs) are the most common cause of inherited blindness worldwide and are caused by genetic defects in about 300 different genes. While targeted next-generation sequencing (NGS) has been demonstrated to be a reliable and efficient method to identify RD disease-causing variants, it doesn't routinely identify pathogenic structural variant as copy number variations (CNVs). Targeted NGS-based CNV detection has become a crucial step for RDs molecular diagnosis, particularly in cases without identified causative single nucleotide or Indels variants. Herein, we report the exome sequencing (ES) data-based read-depth bioinformatic analysis in a group of 30 unrelated Mexican RD patients with a negative or inconclusive genetic result after ES. METHODS: CNV detection was performed using ExomeDepth software, an R package designed to detect CNVs using exome data. Bioinformatic validation of identified CNVs was conducted through a commercially available CNV caller. All identified candidate pathogenic CNVs were orthogonally verified through quantitative PCR assays. RESULTS: Pathogenic or likely pathogenic CNVs were identified in 6 out of 30 cases (20%), and of them, a definitive molecular diagnosis was reached in 5 cases, for a final diagnostic rate of ~17%. CNV-carrying genes included CLN3 (2 cases), ABCA4 (novel deletion), EYS, and RPGRIP1. CONCLUSIONS: Our results indicate that bioinformatic analysis of ES data is a reliable method for pathogenic CNV detection and that it should be incorporated in cases with a negative or inconclusive molecular result after ES.

Early diagnosis of Duchenne muscular dystrophy - A Treat-NMD international workshop.

The diagnosis of Duchenne muscular dystrophy (DMD) is significant at any stage, however an early diagnosis in a presymptomatic or very early phase of DMD, offers unique opportunities and challenges for families and health care providers. Currently, there is limited evidence as to the optimal models of care during this stage of the condition.. To address this, in 2023, Treat-NMD facilitated the Early Diagnosis for DMD project; bringing together 42 experts from across Europe, the US and Australasia, including health care professionals, researchers, and people with lived experience to discuss the complexities of an early or newborn diagnosis of DMD, and provide recommendations regarding approaches to multidisciplinary care. A series of virtual meetings followed by a hybrid workshop resulted in broad recommendations to support clinicians in caring for children and families following an early diagnosis of DMD. The workshop did not define a cut-off for early diagnosis, however much of the discussion focused on diagnoses that occurred prior to 2 years. There is recognition that boys may first present with non-motor symptoms, such as speech delay or neurodevelopmental issues that are secondary to their dystrophinopathy, and therefore this report refers reflects that infants with DMD may be presymptomatic or early symptomatic.