A novel deep intronic variant in LAMA2 identified by RNA sequencing.

LAMA2-related muscular dystrophy is caused by pathogenic variants of the alpha2 subunit of Laminin. This common form of muscular dystrophy is characterized by elevated CK >1000IU/L, dystrophic changes on muscle biopsy, complete or partial absence of merosin staining, and both central and peripheral nervous system involvement. Advancements in genomic testing using NGS and wider application of RNA sequencing has expanded our knowledge of novel non-coding pathogenic variants in LAMA2. RNA sequencing is an increasingly utilized technique to directly analyze the transcriptome, through creation of a complementary DNA (cDNA) from the transcript within a tissue sample. Here we describe a homozygous deep intronic variant that produces a novel splice junction in LAMA2 identified by RNA sequencing analysis in a patient with a clinical phenotype in keeping with LAMA2-related muscular dystrophy. Furthermore, in this case merosin staining was retained suggestive of a functional deficit.

Diagnoses of muscular dystrophy in a veterans health system.

INTRODUCTION/AIMS: Early diagnosis of a chronic neuromuscular disease such as muscular dystrophy (MD) generally excludes an individual from active-duty military service. However, it is not known whether veterans are sometimes diagnosed with milder forms of MD at a later timepoint. We aimed to determine the prevalence of MD in a veterans health system. METHODS: We abstracted clinical and genetic test data on patients who received care for a diagnosis of MD at the North Florida/South Georgia Veterans Health System between 2008 and 2021. We then determined which of these individuals would meet criteria for a definite diagnosis of MD, based on electrodiagnostic testing, muscle biopsy, and genetic testing of the individual or an affected first degree relative. RESULTS: We identified 12 patients with definite MD and 36 with possible or probable MD. The definite cases included myotonic dystrophy type 1 (4), myotonic dystrophy type 2 (3), oculopharyngeal MD (2), Becker MD (1), distal MD (1), and facioscapulohumeral MD (1). At least five of the cases classified as definite developed symptoms after discharge from active duty. DISCUSSION: Clinicians who care for veterans should be knowledgeable about, and have access to, diagnostic testing and treatment options for MD. When conducting MD surveillance, it is important to include veterans health systems as a data source. Mild cases of MD and those of later onset appear to be compatible in some cases with successful completion of military service.

Ambient floor vibration sensing advances the accessibility of functional gait assessments for children with muscular dystrophies.

Muscular dystrophies (MD) are a group of genetic neuromuscular disorders that cause progressive weakness and loss of muscles over time, influencing 1 in 3500-5000 children worldwide. New and exciting treatment options have led to a critical need for a clinical post-marketing surveillance tool to confirm the efficacy and safety of these treatments after individuals receive them in a commercial setting. For MDs, functional gait assessment is a common approach to evaluate the efficacy of the treatments because muscle weakness is reflected in individuals' walking patterns. However, there is little incentive for the family to continue to travel for such assessments due to the lack of access to specialty centers. While various existing sensing devices, such as cameras, force plates, and wearables can assess gait at home, they are limited by privacy concerns, area of coverage, and discomfort in carrying devices, which is not practical for long-term, continuous monitoring in daily settings. In this study, we introduce a novel functional gait assessment system using ambient floor vibrations, which is non-invasive and scalable, requiring only low-cost and sparsely deployed geophone sensors attached to the floor surface, suitable for in-home usage. Our system captures floor vibrations generated by footsteps from patients while they walk around and analyzes such vibrations to extract essential gait health information. To enhance interpretability and reliability under various sensing scenarios, we translate the signal patterns of floor vibration to pathological gait patterns related to MD, and develop a hierarchical learning algorithm that aggregates insights from individual footsteps to estimate a person's overall gait performance. When evaluated through real-world experiments with 36 subjects (including 15 patients with MD), our floor vibration sensing system achieves a 94.8% accuracy in predicting functional gait stages for patients with MD. Our approach enables accurate, accessible, and scalable functional gait assessment, bringing MD progressive tracking into real life.

Genetic blueprint of congenital muscular dystrophies with brain malformations in Egypt: A report of 11 families.

Congenital muscular dystrophies (CMDs) are a group of rare muscle disorders characterized by early onset hypotonia and motor developmental delay associated with brain malformations with or without eye anomalies in the most severe cases. In this study, we aimed to uncover the genetic basis of severe CMD in Egypt and to determine the efficacy of whole exome sequencing (WES)-based genetic diagnosis in this population. We recruited twelve individuals from eleven families with a clinical diagnosis of CMD with brain malformations that fell into two groups: seven patients with suspected dystroglycanopathy and five patients with suspected merosin-deficient CMD. WES was analyzed by variant filtering using multiple approaches including splicing and copy number variant (CNV) analysis. We identified likely pathogenic variants in FKRP in two cases and variants in POMT1, POMK, and B3GALNT2 in three individuals. All individuals with merosin-deficient CMD had truncating variants in LAMA2. Further analysis in one of the two unsolved cases showed a homozygous protein-truncating variant in Feline Leukemia Virus subgroup C Receptor 1 (FLVCR1). FLVCR1 loss of function has never been previously reported. Yet, loss of function of its paralog, FLVCR2, causes lethal hydranencephaly-hydrocephaly syndrome (Fowler Syndrome) which should be considered in the differential diagnosis for dystroglycanopathy. Overall, we reached a diagnostic rate of 86% (6/7) for dystroglycanopathies and 100% (5/5) for merosinopathy. In conclusion, our results provide further evidence that WES is an important diagnostic method in CMD in developing countries to improve the diagnostic rate, management plan, and genetic counseling for these disorders.

Expanding the phenotypic and genotypic spectrum of GGPS1 related congenital muscular dystrophy.

Congenital muscular dystrophies are a group of progressive disorders with wide range of symptoms associated with diverse cellular mechanisms. Recently, biallelic variants in GGPS1 were linked to a distinct autosomal recessive form of muscular dystrophy associated with hearing loss and ovarian insufficiency. In this report, we present a case of a young patient with a homozygous variant in GGPS1. The patient presented with only proximal muscle weakness, and elevated liver transaminases with spared hearing function. The hepatic involvement in this patient caused by a novel deleterious variant in the gene extends the phenotypic and genotypic spectrum of GGPS1 related muscular dystrophy.

Spontaneous mutation in the COL6A2 gene causing Ullrich congenital muscular dystrophy type 1 in a Chinese child: A case report.

RATIONALE: Mutations in the gene encoding type VI collagen cause Bethlem myopathy (MIM 158810) and Ullrich congenital muscular dystrophy (MIM 254090); 2 diseases previously recognized as completely independent, and have been increasingly recognized. However, collagen-related myopathy caused by intron variation in the COL6 gene is rarely reported in China. Ullrich congenital muscular dystrophy is an autosomal recessive disorder that leads to severe muscle weakness with early onset. Thus, children may never walk independently, with proximal joint contractures and significant hyperelastic distal joints, and have early respiratory failure. Therefore, timely diagnosis and treatment are important. We report a spontaneous mutation in the COL6A2 gene causing Ullrich congenital muscular dystrophy type 1 in a pediatric patient. PATIENT CONCERNS: A boy aged 4 years was unable to walk independently, could sit alone for a short time, and his motor development was delayed and had regressed after 1 year of age. He had a high palatal arch and a through palm with localized transverse lines running laterally from the palm. Electromyography showed an impaired neurogenic source, and whole-exon gene sequencing revealed a spontaneous heterozygous mutation in the COL6A2 gene (c.955-2A>G), which was determined to be a pathogenic mutation according to the American Guidelines of the College of Medical Genetics. DIAGNOSES: This child has a delayed motor development, high osprey arch and a through palm with localized transverse lines running laterally from the palm, and regression of motor development after the age of 1 year. Whole exon examination showed spontaneous mutation of the COL6A2 gene; thus, the child was diagnosed with UCMD type 1. INTERVENTIONS: At present, there is no special treatment for this disease, and treatment is mainly symptomatic and supportive. The child underwent home massage, rehabilitation training, oral folic acid tablets, vitamins and coenzyme Q10. OUTCOMES: During the subsequent follow-up period, the patient can now sit alone for a short period of time. LESSONS: We report a case of spontaneous mutation in the COL6A2 gene causing Ullrich congenital muscular dystrophy type 1 in a pediatric patient, expanding the phenotypic spectrum of the disease and enriching the human gene pool.

[Non-ischemic priapism (post-traumatic arteriovenous fistula of the right cavernous body) in the background of Landusy-Dejerine myopathy].

Landouzy-Dejerine myopathy (Facial-shoulder-shoulder myodystrophy) is a disease which causes weakness of the muscles of the shoulder girdle, back and hip muscles, which predisposes patients to an increased risk of injury and disability. The article presents a clinical observation of non-ischemic priapism, which developed as a result of perineal trauma with the formation of a fistula of the right cavernous body in a patient against the background of facial shoulder-shoulder myodystrophy. Methods for the differential diagnosis of this condition are also discussed.

Megaconial congenital muscular dystrophy due to CHKB gene variants, the first report of thirteen Iranian patients.

Megaconial congenital muscular dystrophy (OMIM: 602,541) related to CHKB gene mutation is a newly defined rare autosomal recessive disorder, with multisystem involvement presenting from the neonatal period to adolescence. Choline kinase beta, lipid transport enzyme, catalyzes the biosynthesis of phosphatidylcholine and phosphatidylethanolamine, two major components of the mitochondrial membrane, on which respiratory enzyme activities are dependent. CHKB gene variants lead to loss-of-function of choline kinase b and lipid metabolism defects and mitochondrial structural changes. To date, many megaconial congenital muscular dystrophy cases due to CHKB gene variants have been reported worldwide. We describe thirteen Iranian megaconial congenital muscular dystrophy cases related to CHKB gene variants, including clinical presentations, laboratory and muscle biopsy findings, and novel CHKB gene variants. The most common symptoms and signs included intellectual disability, delayed gross-motor developmental milestones, language skills problems, muscle weakness, as well as autistic features, and behavioral problems. Muscle biopsy examination showed the striking finding of peripheral arrangements of large mitochondria in muscle fibers and central sarcoplasmic areas devoid of mitochondria. Eleven different CHKB gene variants including six novel variants were found in our patients. Despite the rarity of this disorder, recognition of the multisystem clinical presentations combined with characteristic findings of muscle histology can properly guide to genetic evaluation of CHKB gene.

Whole exome sequencing identifies a novel variant in the COL12A1 gene in a family with Ullrich congenital muscular dystrophy 2.

BACKGROUND: Mutations within the COL12A1 gene have been linked with the onset of congenital Ullrich muscular dystrophy 2 (UCMD2) and Bethlem myopathy. The severity of the symptoms exhibited is dependent on the mutation's type and whether it is heterozygous or homozygous. METHODS: We used whole-exome sequencing to identify disease-causing variants in a nine-year-old Iranian patient who had weakness, joint contractures, delayed motor development, and other symptoms. We confirmed the pathogenicity of the identified variant using in silico tools and verified its novelty using various databases. We also performed a co-segregation study and confirmed the presence of the variant in the patient's parents by Sanger sequencing. RESULTS: Our analysis identified a novel homozygous missense variant in the affected patient in COL12A1 (c.8828 C > T; p.Pro2943Leu). This is the second reported family with UCMD2 caused by a mutation in COL12A1. Our findings confirm that this mutation results in significantly more severe symptoms than Bethlem myopathy. CONCLUSION: Our investigation contributes to the expanding body of evidence that links mutations in COL12A1 with UCMD2. Our findings confirm that the homozygous mutation in COL12A1 caused this condition and suggest that genetic testing for this mutation may be useful for diagnosing patients with this disease.

Broad spectrum of phenotype and genotype in Korean α-dystroglycan related muscular dystrophy presenting to a tertiary pediatric neuromuscular center.

α-Dystroglycanopathies are a clinically and genetically heterogeneous group of muscular dystrophies associated with the defective glycosylation of α-dystroglycan (α-DG). Eighteen genes associated with α-dystroglycanopathies have been identified, and the relative prevalence of genetic subtypes varies with ethnicity. Here, we investigated the clinical and genetic characteristics of α-DG-related muscular dystrophy in the Korean pediatric population. We analyzed the clinical characteristics and variant profiles of 42 patients with α-DG-related muscular dystrophies diagnosed by either reduced glycosylation of α-DG and/or genetic confirmation. Genotype-phenotype correlations were explored by a retrospective medical record review. The muscle-eye-brain disease/Fukuyama congenital muscular dystrophy was the most common phenotype (28/42, 66.7%). Homozygous or compound heterozygous variants were detected in 37 patients belonging to 34 unrelated families (37/42; 88.1%). Pathogenic variants were identified in FKTN (n = 24), POMGNT1 (n = 4), GMPPB (n = 4), FKRP (n = 2), POMT1 (n = 2), and ISPD (n = 1). Compound heterozygous retrotransposal insertions and deep-intronic variants in FKTN were the most common genotypes and were associated with severe phenotypes. This study suggests that α-DG-related muscular dystrophy has a wide range of genotypes and phenotypes according to ethnicity. A stratified genetic test according to ethnicity should be considered to diagnose α-DG-related muscular dystrophy.

The Muscular Dystrophy Association's neuroMuscular ObserVational Research Data Hub (MOVR): Design, Methods, and Initial Observations.

BACKGROUND: Neuromuscular disease (NMD) research is experiencing tremendous growth as a result of progress in diagnostics and therapeutics yet there continues to be a significant clinical data shortage for these rare diseases. To maximize the development and impact of new therapies, the Muscular Dystrophy Association (MDA) created the neuroMuscular ObserVational Research Data Hub (MOVR) as an observational research study that collects disease-specific measures from individuals living with NMDs in the United States. OBJECTIVE: This manuscript provides a description of MOVR, participants enrolled in MOVR, and longitudinal data availability. METHODS: MOVR collects longitudinal data from individuals diagnosed with ALS, BMD, DMD, FSHD, LGMD, Pompe disease, or SMA, and who are seen for care at a participating MDA Care Center. Data are entered from medical records into standardized electronic case report forms (eCRFs). These eCRFs capture participants' demographics, diagnostic journeys, clinical visits, and discontinuation from the study. RESULTS: From January 2019 to May 2022, MOVR collected data from 50 participating care centers and 1,957 participants. Data from 1,923 participants who participated in MDA's pilot registry were migrated into MOVR, creating a total of 3,880 participants in MOVR. Initial analysis of aggregated data demonstrated that 91% of eCRFs were complete. Forty-three percent of participants had 3 or more encounters and 50% of all encounters were 5 months or less from the previous encounter. DISCUSSION: As a centralized data hub for multiple NMDs, MOVR serves as a platform that can be used to inform disease understanding, guide clinical trial design, and accelerate drug development for NMDs.

The bi-directional relationship between sleep and inflammation in muscular dystrophies: A narrative review.

Muscular dystrophies vary in presentation and severity, but are associated with profound disability in many people. Although characterised by muscle weakness and wasting, there is also a very high prevalence of sleep problems and disorders which have significant impacts on quality of life in these individuals. There are no curative therapies for muscular dystrophies, with the only options for patients being supportive therapies to aid with symptoms. Therefore, there is an urgent need for new therapeutic targets and a greater understanding of pathogenesis. Inflammation and altered immunity are factors which have prominent roles in some muscular dystrophies and emerging roles in others such as type 1 myotonic dystrophy, signifying a link to pathogenesis. Interestingly, there is also a strong link between inflammation/immunity and sleep. In this review, we will explore this link in the context of muscular dystrophies and how it may influence potential therapeutic targets and interventions.

The role of magnetic resonance imaging in the diagnostic work-out of myopathies: differential diagnosis between inflammatory myopathies and muscular dystrophies.

OBJECTIVES: The differential diagnosis between idiopathic inflammatory myopathies (IIM) and muscular dystrophies (MD) may be challenging. We analysed the potential role of muscular magnetic resonance imaging (MRI) in the differential diagnosis between IIM and MD. METHODS: MRI of patients (91 IIM and 43 MD), studied with a standardised protocol, have been collected. The presence of oedema, muscular atrophy and intramuscular adipose changes were evaluated. Moreover, we computed a composite score for each MRI item to better discriminate between the two diseases. RESULTS: Oedema was significantly more prevalent in IIM compared with MD in pelvis muscles (p<0.001), anterior lodge and medial lodges (p=0.044) of the thighs. Adipose infiltration/substitution and muscular atrophy were more prevalent in MD, in particular adipose tissue was prevalent in all the compartments of the thighs (p<0.05), atrophy was prevalent at the thighs and pelvis muscles (p<0.001). The probability of IIM increased with higher oedema score and decreased with higher atrophy and intramuscular adipose infiltration/substitution scores. CONCLUSIONS: A different distribution of muscular involvement between IIM and MD has been identified. Muscular MRI may be useful in the differential diagnosis, potentially reducing the number of muscular biopsies that may be reserved only for doubtful cases.

Causes of HyperCKemia in Children: A Retrospective Cohort Study.

Background and Objectives: Creatine kinase (CK) is a commonly used screening test for neuromuscular disorders (NMDs). However, hyperCKemia can result from several pathologic and physiologic causes. We analyzed neuromuscular disorders in noninfant children with hyperCKemia including those with no weakness and mild CK elevations (<5 times the upper limit of normal). We hypothesized that children with mild CK elevation and no weakness would be unlikely to have neuromuscular disorders and require additional evaluation. Methods: We retrospectively evaluated patients between 1 and 18 years of age seen at a single children's hospital over a 3-calendar-year period with initial total CK values greater than the upper limit of normal with at least 2 years of follow-up data. Final diagnoses were analyzed and associations with possible risk factors assessed. Receiver operating characteristic curves were generated to assess altering CK cutoff values. Results: Of 260 subjects with hyperCKemia, 18 had a neuromuscular disorder (6.9%, 95% confidence interval [CI] 4.2%-10.9%). Of 166 subjects with CK <5 times the upper limit of normal and no weakness, 8 had a neuromuscular disorder (4.8%, 95% CI 2.3%-9.6%). Weakness (odds ratio [OR] 32.5, 95% CI 4-385, P = .0002), and family history of neuromuscular disorders (OR not calculable, P = .0003) were associated with neuromuscular disorders. An optimal CK threshold of 777 was identified on receiver operating characteristic curve analysis (sensitivity of 72% and specificity of 64%). The most commonly identified neuromuscular disorders were muscular dystrophies, inflammatory myopathies, and metabolic myopathies. Conclusion: Most children with hyperCKemia will not be diagnosed with a neuromuscular disorder, but a significant minority even with mild hyperCKemia and without weakness may warrant additional evaluation.

Mild limb girdle muscular dystrophy R9 phenotype caused by novel compound heterozygous FKRP gene mutation.

Fukutin-related protein (FKRP) mutations cause a broad spectrum of muscular dystrophies, from a relatively mild limb-girdle muscular dystrophy type 9 (LGMDR9) to severe congenital muscular dystrophy (CMD). This study aims to report two siblings belonging to a non-consanguineous Tunisian family harboring a novel compound heterozygous FKRP variant and presenting a mild LGDMR9 phenotype. For mutation screening, massive parallel sequencing was performed, followed by Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) to validate the existence of the discovered variants. The absence of alpha-dystroglycan was determined by immunohistochemistry. Brain and thigh magnetic resonance imaging (MRI) were performed to detect thigh and brain abnormalities. The two siblings had a late age at onset and clinical examination showed that the pelvic girdles had a predominantly proximal and symmetrical distribution of weakness without cardiac or respiratory involvement. They both had a modified Gardner-Medwin Walton Scale mGMWS grade of 4 and a modified Rankin Scale (mRS) score of 1. The DNA sequencing revealed a novel deletion of exons 2 and 3 in one allele and a missense mutation c.1364C > A, which has been reported to be responsible for congenital muscular dystrophy and mental retardation on the second allele. The simultaneous presence of the two variations in the two cases suggests that the variants segregate with the pathophysiology.

Megaconial congenital muscular dystrophy due to novel CHKB variants: a case report and literature review.

BACKGROUND: Choline kinase beta (CHKB) catalyzes the first step in the de novo biosynthesis of phosphatidyl choline and phosphatidylethanolamine via the Kennedy pathway. Derangement of this pathway might also influence the homeostasis of mitochondrial membranes. Autosomal recessive CHKB mutations cause a rare form of congenital muscular dystrophy known as megaconial congenital muscular dystrophy (MCMD). CASE PRESENTATION: We describe a novel proband presenting MCMD due to unpublished CHKB mutations. The patient is a 6-year-old boy who came to our attention for cognitive impairment and slowly progressive muscular weakness. He was the first son of non-consanguineous healthy parents from Sri Lanka. Neurological examination showed proximal weakness at four limbs, weak osteotendinous reflexes, Gowers' maneuver, and waddling gate. Creatine kinase levels were mildly increased. EMG and brain MRI were normal. Left quadriceps skeletal muscle biopsy showed a myopathic pattern with nuclear centralizations and connective tissue increase. Histological and histochemical staining suggested subsarcolemmal localization and dimensional increase of mitochondria. Ultrastructural analysis confirmed the presence of enlarged ("megaconial") mitochondria. Direct sequencing of CHKB identified two novel defects: the c.1060G > C (p.Gly354Arg) substitution and the c.448-56_29del intronic deletion, segregating from father and mother, respectively. Subcloning of RT-PCR amplicons from patient's muscle RNA showed that c.448-56_29del results in the partial retention (14 nucleotides) of intron 3, altering physiological splicing and transcript stability. Biochemical studies showed reduced levels of the mitochondrial fission factor DRP1 and the severe impairment of mitochondrial respiratory chain activity in patient's muscle compared to controls. CONCLUSIONS: This report expands the molecular findings associated with MCMD and confirms the importance of considering CHKB variants in the differential diagnosis of patients presenting with muscular dystrophy and mental retardation. The clinical outcome of MCMD patients seems to be influenced by CHKB molecular defects. Histological and ultrastructural examination of muscle biopsy directed molecular studies and allowed the identification and characterization of an intronic mutation, usually escaping standard molecular testing.

LAMA2-related muscular dystrophy mimicking multiple sclerosis.

Laminin-alpha2-related muscular dystrophy (LAMA2-MD) is a genetic condition due to reduced LAMA2, a protein found throughout the nervous system. Late-onset LAMA2-MD may present with proximal muscle weakness, joint contractures, neuropathy, epilepsy and/or cardiorespiratory issues, and is less common than the neonatal form. We describe a novel phenotype of LAMA2-MD with progressive myelopathy and spinal cord abnormalities.A woman was referred for evaluation of multiple sclerosis (MS) with progressive gait difficulty and abnormal neuroimaging showing white matter abnormalities in the brain and spinal cord. Ancillary testing was not consistent with primary neuroinflammatory disorders, systemic autoimmunity or infection. Metabolic workup revealed low cyanocobalamin. Genetic testing identified two LAMA2-MD variants.Genetic disorders can mimic treatable neurological conditions. Chronic progressive course, involvement of the peripheral and central nervous systems, and confluent white matter abnormalities should be investigated with molecular testing that includes LAMA2 sequencing to ensure proper diagnosis and management.

Autosomal dominant Ullrich congenital muscular dystrophy due to a de novo mutation in COL6A3 gene. A case report.

Mutations in the genes encoding collagen VI cause Bethlem myopathy (MIM 158810), Ullrich congenital muscular dystrophy (MIM 254090), and myosclerosis myopathy (MIM #255600). BM is a dominantly inherited disorder, characterised by proximal muscle weakness and joint contractures mainly involving the elbows, ankles, and fingers, which usually follows a relatively mild course. By contrast, UCMD is a severe muscular dystrophy characterized by early onset, rapidly progressive muscle wasting and weakness, proximal joint contractures and distal joint hyperlaxity. Rapid progression usually leads to early death due to respiratory failure. UCMD is usually inherited as an autosomal recessive trait though dominant de novo heterozygous variants have recently been reported. We describe a further patient with UCMD classical presentation who showed, at the NGS analysis, the de novo variant c.6210+1G > A in the intron 16 of the gene COL6A3, known in the literature as pathogenic (VCV0000949S6.5).