The Hidden Disease: Delayed Diagnosis in Duchenne Muscular Dystrophy and Co-Occurring Conditions

Dmd mdx mice have defective oligodendrogenesis, delayed myelin compaction and persistent hypomyelination

Duchenne muscular dystrophy (DMD) is caused by mutations in the DMD gene, resulting in the loss of dystrophin, a large cytosolic protein that links the cytoskeleton to extracellular matrix receptors in skeletal muscle. Aside from progressive muscle damage, many patients with DMD also have neurological deficits of unknown etiology. To investigate potential mechanisms for DMD neurological deficits, we assessed postnatal oligodendrogenesis and myelination in the Dmdmdx mouse model. In the ventricular-subventricular zone (V-SVZ) stem cell niche, we found that oligodendrocyte progenitor cell (OPC) production was deficient, with reduced OPC densities and proliferation, despite a normal stem cell niche organization. In the Dmdmdx corpus callosum, a large white matter tract adjacent to the V-SVZ, we also observed reduced OPC proliferation and fewer oligodendrocytes. Transmission electron microscopy further revealed significantly thinner myelin, an increased number of abnormal myelin structures and delayed myelin compaction, with hypomyelination persisting into adulthood. Our findings reveal alterations in oligodendrocyte development and myelination that support the hypothesis that changes in diffusion tensor imaging seen in patients with DMD reflect developmental changes in myelin architecture.

Difficulties in social cognitive functioning among pediatric patients with muscular dystrophies

Introduction

Pediatric muscular dystrophies (MDs) are a heterogeneous group of rare neuromuscular diseases characterized by progressive muscle degeneration. A neuropsychosocial approach is crucial for these patients due to associated cognitive, behavioral, and psychiatric comorbidities; however, the social cognitive domain has not been adequately addressed.

Methods

This study aimed to analyze on social cognition performance in a pediatric MD patient cohort. This cross-sectional study included 32 pediatric patients with MD and 32 matched-healthy controls. The Social Perception Domain of the NEPSY-II, the Reading the Mind in the Eyes Test-Child and Happé's Strange Stories Test were administered. General intelligence and behavioral and emotional symptoms were controlled for to eliminate covariables' possible influence. The assessments were performed remotely.

Results

Children with MDs performed significantly worse on most of the social cognition tasks. The differences found between the groups could be explained by the level of general intelligence for some aspects more related to theory of mind (ToM) (TM NEPSY-II: F = 1.703, p = .197; Verbal task: F = 2.411, p = .125; RMET-C: F = 2.899, p = .094), but not for emotion recognition. Furthermore, these differences were also independent of behavioral and emotional symptoms.

Discussion

In conclusion, social cognition is apparently impaired in pediatric patients with MD, both for emotion recognition and ToM. Screening assessment in social cognition should be considered to promote early interventions aimed at improving these patient's quality of life.

Social cognition in DMD and BMD dystrophinopathies: A cross-sectional preliminary study

Objective: The dystrophinopathies called Duchenne and Becker muscular dystrophies (DMD/BMD) are rare, progressive, incurable, and life-limiting paediatric-onset neuromuscular diseases. These diseases have long been associated with specific neuropsychological deficits. However, the performance of these patients in the social cognition domain has not been properly investigated. Thus, the main objective of this study was to compare the performance on social cognition between DMD/BMD patients and healthy age-matched boys. Method: This cross-sectional study included 20 DMD/BMD children and adolescents and 20 healthy controls. The protocol included the Social Perception Domain of the NEPSY-II, the Reading the Mind in the Eyes Test - Child and Happé's Strange Stories test. General intelligence was controlled to eliminate the possible influence of covariables. All the assessments were performed remotely. Results: Most social cognition tasks were worse in patients with DMD/BMD than in matched healthy controls. These differences remained even after controlling for the general intelligence variable, with the exception of Total Disgust Errors (F = 1.462, p = .234, η2p= .038) and Verbal task (F = 1.820, p = .185, η2p= .047) scores from the NEPSY-II. Conclusions: This is the first study to demonstrate that the neuropsychological domain of social cognition is impaired in DMD/BMD patients, independent of the level of general intelligence. Screening assessments in DMD/BMD patients should be promoted to allow social cognition difficulties to be detected at an early stage to enhance patients' quality of life and social development.

The Early Care (0-3 Years) In Duchenne Muscular Dystrophy Meeting Report

Objective

This report summarizes the key discussions from the "Early Care (0-3 years) in Duchenne Muscular Dystrophy" meeting, which aimed to address the challenges and opportunities in the diagnosis and care of Duchenne muscular dystrophy (DMD) and female carriers within the 0-3-year age group.

Methods

The meeting brought together experts and healthcare providers who shared insights, discussed advancements in DMD care, and identified research needs. Presentations covered diagnostic challenges, approved therapies, clinical trials, identification of young female carriers, and the importance of clinical care and support for families.

Results

The meeting highlighted the importance of timely diagnosis and the lack of evidence-based guidelines for the care of children with DMD aged 0-3 years. Diagnostic challenges were discussed, including delays in receiving a DMD diagnosis and disparities based on ethnicity. The potential benefits and process of newborn screening were addressed.Approved therapeutic interventions, such as corticosteroids and exon-skipping drugs, were explored, with studies indicating the potential benefits of early initiation of corticosteroid therapy and the safety of exon-skipping drugs in DMD. Clinical trials involving infants and young boys were discussed, focusing on drugs like ataluren, vamorolone, and gene therapies.The meeting emphasized the importance of clinical care and support for families, including comprehensive information provision, early intervention services, and individualized support. The identification and care of young female carriers were also addressed.

Conclusion

The meeting provided a platform for experts and healthcare providers to discuss and identify key aspects of early care for children with DMD aged 0-3 years. The meeting emphasized the need for early diagnosis, evidence-based guidelines, and comprehensive care and support for affected children and their families. Further research, collaboration, and the development of consensus guidelines are needed to improve early diagnosis, treatment, and outcomes in this population.

Detecting early signs in Duchenne muscular dystrophy: comprehensive review and diagnostic implications

Despite the early onset of clinical signs suggestive of Duchenne muscular dystrophy (DMD), a diagnosis is often not made until four years of age or older, with a diagnostic delay of up to two years from the appearance of the first symptoms. As disease-modifying therapies for DMD become available that are ideally started early before irreversible muscle damage occurs, the importance of avoiding diagnostic delay increases. Shortening the time to a definite diagnosis in DMD allows timely genetic counseling and assessment of carrier status, initiation of multidisciplinary standard care, timely initiation of appropriate treatments, and precise genetic mutation characterization to assess suitability for access to drugs targeted at specific mutations while reducing the emotional and psychological family burden of the disease. This comprehensive literature review describes the early signs of impairment in DMD and highlights the bottlenecks related to the different diagnostic steps. In summary, the evidence suggests that the best mitigation strategy for improving the age at diagnosis is to increase awareness of the early symptoms of DMD and encourage early clinical screening with an inexpensive and sensitive serum creatine kinase test in all boys who present signs of developmental delay and specific motor test abnormality at routine pediatrician visits.

The Importance of Implementing a Transition Strategy for Patients with Muscular Dystrophy: From Child to Adult-Insights from a Tertiary Centre for Rare Neurological Diseases

Progress in the field of muscular dystrophy (MD) using a multidisciplinary approach based on international standards of care has led to a significant increase in the life expectancy of patients. The challenge of transitioning from pediatric to adult healthcare has been acknowledged for over a decade, yet it continues to be a last-minute concern. Currently, there is no established consensus on how to evaluate the effectiveness of the transition process. Our study aimed to identify how well patients are prepared for the transition and to determine their needs. We conducted a descriptive, cross-sectional study on 15 patients aged 14 to 21 years. The patients completed a sociodemographic and a Transition Readiness Assessment Questionnaire (TRAQ). We also analyzed the comorbidities of these patients. Our study revealed that only 46.7% of the patients had engaged in a conversation with a medical professional, namely, a child neurologist, about transitioning. A total of 60% of the participants expressed having confidence in their self-care ability. However, the median TRAQ score of 3.6 shows that these patients overestimate themselves. We emphasize the necessity for a slow, personalized transition led by a multidisciplinary team to ensure the continuity of state-of-the-art care from pediatric to adult healthcare services and the achievement of the highest possible quality of life for these patients.

Time to diagnosis of Duchenne muscular dystrophy in Austria and Germany

Duchenne muscular dystrophy (DMD) is an X-linked genetic disorder manifesting in early childhood with progressive muscular weakness and atrophy, and resulting in early loss of ambulation. The collection and evaluation of epidemiological data for this disease is crucial for an early diagnosis and disease management. In Germany, data are collected via the TREAT-NMD DMD patient registry ( www.dmd-register.de ). In contrast, data collection in Austria has not yet been performed systematically. For collecting data from Austrian DMD patients, an online survey of the patient's caregivers was conducted. Data of 57 patients were collected entailing initial symptoms, diagnosis and therapeutic measures. Comparable data has been collected for Germany via the TREAT-NMD DMD patient registry. 57 DMD patients aged 4-34 years completed the Austrian survey. On average, first symptoms of the disease appeared at the age of 3.1 years. As the most frequent first symptom, 46% of the patients described problems in climbing stairs. In 40% of the patients, DMD was diagnosed early due to an accidentally detected hyperCKemia in infancy or early childhood. Corticosteroids represented the main therapeutic option in our cohort. At the time of the survey, only 52% of the patients were treated with corticosteroids. Patients from Germany reported that first symptoms appeared at the age of 3.06 years. Diagnosis was established by genetic testing or muscle biopsy. 47% of the patients were treated with corticosteroids. Time between first symptoms and diagnosis was 7 months in Austria, and 4.7 months in Germany, respectively. Compared to earlier international studies, the Austrian data show encouraging results regarding earlier start of corticosteroid therapy in a larger percentage of patients. Austrian and German data show a trend towards an earlier diagnosis of DMD, while the age at symptom onset was similar to previous studies. The collection and evaluation of epidemiological data of DMD patients is important and will hopefully contribute to accelerate DMD diagnosis and treatment access for the patients.