A self-reported Brazilian registry of 5q-spinal muscular atrophy: data on natural history, genetic characteristics, and multidisciplinary care.

Background:  Spinal muscular atrophy linked to chromosome 5q (SMA-5q) is a neurodegenerative disorder caused by mutations in the gene.

Objective:  To describe the key demographic, clinical and genetic characteristics, as well as natural history data of patients with SMA-5q.

Methods:  Up to January 2022, 706 patients with confirmed genetic diagnosis of SMA-5q, or their parents, completed a self-reported questionnaire on natural history, genetic characteristics, drug treatments, and multidisciplinary care.

Longitudinal data collection in pediatric and adult patients with 5q spinal muscular atrophy in Latin America: LATAM RegistrAME study - a clinical registry study protocol.

Spinal muscular atrophy is a rare hereditary neurodegenerative disease characterized by progressive motor neuron loss. The most common form of SMA is linked to 5q (5q-SMA) and is classified into subtypes according to the age of onset and maximum motor function achieved. The severity ranges from progressive infantile paralysis and premature death (type 1) to limited motor neuron loss in adults (type 4).

Myosin ATPase inhibition fails to rescue the metabolically dysregulated proteome of nebulin-deficient muscle.

Nemaline myopathy (NM) is a genetic muscle disease, primarily caused by mutations in the NEB gene (NEB-NM) and with muscle myosin dysfunction as a major molecular pathogenic mechanism. Recently, we have observed that the myosin biochemical super-relaxed state was significantly impaired in NEB-NM, inducing an aberrant increase in ATP consumption and remodelling of the energy proteome in diseased muscle fibres. Because the small-molecule Mavacamten is known to promote the myosin super-relaxed state and reduce the ATP demand, we tested its potency in the context of NEB-NM.

Cross-sectional survey study of the natural history of LAMA2-related dystrophy.

Background: LAMA2-related dystrophies (LAMA2-RD) are a rare group of neuromuscular disorders with a broad spectrum of phenotype severity, ranging from mild to severe. We performed a cross-sectional study of LAMA2-RD through motor function and pulmonary tests to establish the disease's natural history.

Methods: Forty-four individuals with LAMA2-RD were included and evaluated once through functional outcome measures including Motor Function Measure 32 (MFM32), Revised Upper Limb Module (RULM), goniometry, and Forced Vital Capacity (FVC).

Integrated Approaches and Practical Recommendations in Patient Care Identified with 5q Spinal Muscular Atrophy through Newborn Screening.

In recent years, significant progress has been made in 5q Spinal Muscular Atrophy therapeutics, emphasizing the importance of early diagnosis and intervention for better clinical outcomes. Characterized by spinal cord motor neuron degeneration, 5q-SMA leads to muscle weakness, swallowing difficulties, respiratory insufficiency, and skeletal deformities. Recognizing the pre-symptomatic phases supported by screening and confirmatory genetic tests is crucial for early diagnosis.

Clinical and molecular characterization of limb-girdle muscular dystrophy 2G/R7 in a large cohort of Brazilian patients.

Limb-girdle muscular dystrophy type 2G/R7 (LGMD2G/R7) is an ultra-rare condition initially identified within the Brazilian population. We aimed to expand clinical and genetic information about this disease, including its worldwide distribution. A multicenter historical cohort study was performed at 13 centers in Brazil in which data from index cases and their affected relatives from consecutive families with LGMD2G/R7 were reviewed from July 2017 to August 2023.

Gene-based therapies for neuromuscular disorders.

Neuromuscular diseases (NMD) include a broad group of medical conditions with both acquired and genetic causes. In recent years, important advances have been made in the treatment of genetically caused NMD, and most of these advances are due to the implementation of therapies aimed at gene regulation. Among these therapies, gene replacement, small interfering RNA (siRNA), and antisense antinucleotides are the most promising approaches.

Consensus from the Brazilian Academy of Neurology for the diagnosis, genetic counseling, and use of disease-modifying therapies in 5q spinal muscular atrophy.

Spinal muscular atrophy linked to chromosome 5 (SMA-5q) is an autosomal recessive genetic disease caused by mutations in the . SMA-5q is characterized by progressive degeneration of the spinal cord and bulbar motor neurons, causing severe motor and respiratory impairment with reduced survival, especially in its more severe clinical forms. In recent years, highly effective disease-modifying therapies have emerged, either acting by regulating the splicing of exon 7 of the gene or adding a copy of the gene through gene therapy, providing a drastic change in the natural history of the disease.

Unraveling the Genetic Tapestry of a Village Legend.

In the heart of the emerald expanse of rural Brazil, where I spent my childhood in a humble village, a chilling legend clung to the corners of every home, whispering of a blighted lineage. This unfortunate family bore a strange malady-a gradual forfeiture of their ability to walk-a lamentable curse that extended its icy fingers through 5 harrowed generations.

Human skeletal myopathy myosin mutations disrupt myosin head sequestration.

Myosin heavy chains encoded by MYH7 and MYH2 are abundant in human skeletal muscle and important for muscle contraction. However, it is unclear how mutations in these genes disrupt myosin structure and function leading to skeletal muscle myopathies termed myosinopathies. Here, we used multiple approaches to analyze the effects of common MYH7 and MYH2 mutations in the light meromyosin (LMM) region of myosin.

Abnormal myosin post-translational modifications and ATP turnover time associated with human congenital myopathy-related RYR1 mutations.

Aim: Conditions related to mutations in the gene encoding the skeletal muscle ryanodine receptor 1 (RYR1) are genetic muscle disorders and include congenital myopathies with permanent weakness, as well as episodic phenotypes such as rhabdomyolysis/myalgia. Although RYR1 dysfunction is the primary mechanism in RYR1-related disorders, other downstream pathogenic events are less well understood and may include a secondary remodeling of major contractile proteins. Hence, in the present study, we aimed to investigate whether congenital myopathy-related RYR1 mutations alter the regulation of the most abundant contractile protein, myosin.

Clinical Classification of Variants in the Valosin-Containing Protein Gene Associated With Multisystem Proteinopathy.

Background And Objectives: Pathogenic variants in the valosin-containing protein () gene cause a phenotypically heterogeneous disorder that includes myopathy, motor neuron disease, Paget disease of the bone, frontotemporal dementia, and parkinsonism termed multisystem proteinopathy. This hallmark pleiotropy makes the classification of novel variants challenging. This retrospective study describes and assesses the effect of 19 novel or nonpreviously clinically characterized variants identified in 28 patients (26 unrelated families) in the retrospective VCP International Multicenter Study.

Brain MRI Abnormalities, Epilepsy and Intellectual Disability in LAMA2 Related Dystrophy - a Genotype/Phenotype Correlation.

Background: LAMA2-related muscular dystrophy is a disorder that causes muscle weakness and varies in severity, from a severe, congenital type to a milder, late-onset form. However, the disease does not only affect the muscles, but has systemic involvement and can lead to alterations such as brain malformation, epilepsy and intellectual disability.

Objective: Describe the frequency of cortical malformations, epilepsy and intellectual disability in LAMA2-RD in a Brazilian cohort and correlate the neurological findings to genetic and motor function.

Muscle Ultrasound Changes Correlate With Functional Impairment in Spinal Muscular Atrophy.

Objective: We investigated ultrasound patterns of muscle involvement in different types of spinal muscular atrophy (SMA) and their correlation with functional status to determine the pattern of muscle compromise in patients with SMA and the potential role of ultrasound to evaluate disease progression.

Methods: We examined muscles (biceps brachii, rectus femoris, diaphragm, intercostals and thoracic multifidus) of 41 patients with SMA (types 1 to 4) and 46 healthy age- and sex-matched control individuals using B-mode ultrasound for gray-scale analysis (GSA), area (biceps brachii and rectus femoris) and diaphragm thickening ratio. Functional scales were applied to patients only.

Hypoglycemia in Patients With LAMA2-CMD.

Background: Hypoglycemia has been reported in patients with LAMA2-CMD, but the frequency, risk factors, and correlation to genotype/phenotype have not been systematically assessed to date.

Methods: A retrospective cohort study was performed on 48 patients with LAMA2-CMD. Patients were divided into two groups: a hypoglycemic group, with at least one episode of hypoglycemia, and a nonhypoglycemic group.

Clinical Manifestation of Nebulin-Associated Nemaline Myopathy.

Background And Objectives: Nemaline myopathy (NM) is a genetically heterogeneous inherited myopathy related with at least 12 genes, whereas pathogenic variants in gene are the most common genetic cause. The clinical spectrum of NM caused by NEB pathogenic variants (NM-) is very broad, ranging from mild to severe presentations manifesting with generalized weakness, as well as respiratory and bulbar involvement. There is currently not enough data regarding the progression of the disease.

Challenges and recommendations to increasing the use of exome sequencing and whole genome sequencing for diagnosing rare diseases in Brazil: an expert perspective.

Early diagnosis of genetic rare diseases is an unmet need in Brazil, where an estimated 10-13 million people live with these conditions. Increased use of chromosome microarray assays, exome sequencing, and whole genome sequencing as first-tier testing techniques in suitable indications can shorten the diagnostic odyssey, eliminate unnecessary tests, procedures, and treatments, and lower healthcare expenditures. A selected panel of Brazilian experts in fields related to rare diseases was provided with a series of relevant questions to address before a multi-day conference.

Safety and efficacy of risdiplam in patients with type 1 spinal muscular atrophy (FIREFISH part 2): secondary analyses from an open-label trial.

Background: Risdiplam is an orally administered therapy that modifies pre-mRNA splicing of the survival of motor neuron 2 (SMN2) gene and is approved for the treatment of spinal muscular atrophy. The FIREFISH study is investigating the safety and efficacy of risdiplam in treated infants with type 1 spinal muscular atrophy versus historical controls. The primary endpoint of part 2 of the FIREFISH study showed that infants with type 1 spinal muscular atrophy attained the ability to sit without support for at least 5 s after 12 months of treatment.