Publications by authors named "Sub Subramony"

Recent investigations have defined the pathophysiological basis of many hereditary ataxias (HAs), including loss-of-function as well as gain-of-function mechanisms at either the RNA or protein level. Preclinical studies have assessed gene editing, gene and protein replacement, gene enhancement, and gene knockdown strategies. Methodologies include viral vector delivery of genes, oligonucleotide therapies, cell-penetrating peptides, synthetic transcription factors, and technologies to deliver therapies to defined targets.

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Objective: The objective of the study is to characterize the pathomechanisms underlying actininopathies. Distal myopathies are a group of rare, inherited muscular disorders characterized by progressive loss of muscle fibers that begin in the distal parts of arms and legs. Recently, variants in a new disease gene, ACTN2, have been shown to cause distal myopathy.

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Article Synopsis
  • Clinical trials for spinocerebellar ataxias (SCA) need better endpoints to measure early disease progression and effectiveness of treatments, as current measures focus on later stages.
  • The READISCA consortium found that advanced multimodal magnetic resonance imaging (MRI) can track changes in brain structure and function over 6 months in participants with early-stage SCA mutations, indicating disease progression.
  • Results showed significant differences in microstructural changes between SCA patients and controls, suggesting that diffusion MRI could reduce the sample size needed for future trials compared to traditional assessments like the Scale for Assessment and Rating of Ataxia (SARA).
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Background: Most published reports on SAMD9L-related ataxia-pancytopenia syndrome (ATXPC) have emphasized the hematologic findings. Fewer details are known about the progression of neurologic manifestations and methods for monitoring them.

Cases: We present six individuals from two families transmitting a heterozygous variant in SAMD9L, exhibiting clinical variations in their hematologic and neurologic findings.

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Objectives: Friedreich ataxia (FRDA) is a rare genetic disorder caused by mutations in the FXN gene, leading to progressive coordination loss and other symptoms. The recently approved omaveloxolone targets this condition but is limited to patients over 16 years of age, highlighting the need for pediatric treatments due to the disorder's early onset and more rapid progression in children. This population also experiences increased non-neurological complications; the FACHILD study aimed to augment and expand the knowledge about the natural history of the disease and clinical outcome assessments for trials in children in FRDA.

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We examined the clinical features of Friedreich ataxia (FRDA) patients who present first with cardiac disease in order to understand the earliest features of the diagnostic journey in FRDA. We identified a group of subjects in the FACOMS natural history study whose first identified clinical feature was cardiac. Only 0.

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Background: Fatigue is a prevalent and debilitating symptom in neurological disorders, including spinocerebellar ataxias (SCAs). However, the risk factors of fatigue in the SCAs as well as its impact have not been well investigated.

Objectives: To study the prevalence of fatigue in SCAs, the factors contributing to fatigue, and the influence of fatigue on quality of life.

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Background: Roussy-Lévy syndrome (RLS) is characterized by postural hand tremor seen in patients with familial autosomal dominant Charcot-Marie-Tooth (CMT) neuropathy.

Phenomenology Shown: This video demonstrates irregular, jerky bilateral kinetic, postural, rest tremor affecting the right > left hand, along with pes cavus and gait ataxia in a patient with CMT disease.

Educational Value: Pes cavus, tendon areflexia, sensory ataxia, and upper limb tremor should prompt consideration of CMT neuropathy.

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Article Synopsis
  • - Distal myopathies are rare inherited disorders that cause muscle fiber loss starting in the extremities, linked to variants in a new gene previously associated solely with heart conditions, which encodes a key muscle protein.
  • - The study aims to understand the mechanisms behind these disorders by testing various genetic variants in muscle cell models and correlating them with clinical data from affected patients.
  • - Findings indicate that certain genetic changes linked to dominant forms of the disease cause toxic protein aggregates, suggesting these variants should be considered harmful, while also highlighting the need for further research into other potential disease mechanisms.
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Gene therapy is a potential treatment for Friedreich ataxia, with multiple programs on the horizon. The purpose of this study was to collect opinions about gene therapy from individuals 14 years or older with Friedreich ataxia or parents/caregivers of Friedreich ataxia patients who were diagnosed as children 17 or younger. Participants were asked to complete a survey after reading brief educational materials regarding gene therapy.

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The Cerebellar Cognitive Affective/Schmahmann Syndrome (CCAS) manifests as impaired executive control, linguistic processing, visual spatial function, and affect regulation. The CCAS has been described in the spinocerebellar ataxias (SCAs), but its prevalence is unknown. We analyzed results of the CCAS/Schmahmann Scale (CCAS-S), developed to detect and quantify CCAS, in two natural history studies of 309 individuals Symptomatic for SCA1, SCA2, SCA3, SCA6, SCA7, or SCA8, 26 individuals Pre-symptomatic for SCA1 or SCA3, and 37 Controls.

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Background And Objectives: To develop a valid, disease-specific, patient-reported outcome (PRO) measure for adolescents and adults with Friedreich ataxia (FA) for use in therapeutic trials.

Methods: We conducted semistructured qualitative interviews and a national cross-sectional study of individuals with FA to determine the most prevalent and burdensome symptoms and symptomatic themes to this population. These symptoms and symptomatic themes were included as questions in the first version of the Friedreich's Ataxia-Health Index (FA-HI).

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Background: Myotonic dystrophy type 1 results from an RNA gain-of-function mutation, in which DM1 protein kinase (DMPK) transcripts carrying expanded trinucleotide repeats exert deleterious effects. Antisense oligonucleotides (ASOs) provide a promising approach to treatment of myotonic dystrophy type 1 because they reduce toxic RNA levels. We aimed to investigate the safety of baliforsen (ISIS 598769), an ASO targeting DMPK mRNA.

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Background And Objectives: In spinocerebellar ataxia, ataxia onset can be preceded by mild clinical manifestation, cerebellar and/or brainstem alterations, or biomarker modifications. READISCA is a prospective, longitudinal observational study of patients with spinocerebellar ataxia type 1 (SCA1) and 3 (SCA3) to provide essential markers for therapeutic interventions. We looked for clinical, imaging, or biological markers that are present at an early stage of the disease.

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Objectives: Friedreich ataxia is (FRDA) an autosomal recessive neurodegenerative disorder associated with intrinsic oxidative damage, suggesting that decreasing lipid peroxidation (LPO) might ameliorate disease progression. The present study tested the ability of RT001, a deuterated form of linoleic acid (D2-LA), to alter disease severity in patients with FRDA in a double-blind placebo-controlled trial.

Methods: Sixty-five subjects were recruited across six sites and received either placebo or active drug for an 11-month study.

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Background And Objectives: To determine the prevalence and relative importance of symptoms experienced by children and adults with Friedreich ataxia (FA) and to identify factors associated with a higher burden of disease.

Methods: We conducted qualitative interviews with individuals with FA and caregivers of pediatric individuals with FA to identify potential symptoms of importance to those living with FA. We subsequently performed a cross-sectional study to assess which symptoms have the highest prevalence and importance in FA and to determine which factors are associated with a higher burden of disease.

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Introduction: Drug development for neurodegenerative diseases such as Friedreich's ataxia (FRDA) is limited by a lack of validated, sensitive biomarkers of pharmacodynamic response in affected tissue and disease progression. Studies employing neuroimaging measures to track FRDA have thus far been limited by their small sample sizes and limited follow up. TRACK-FA, a longitudinal, multi-site, and multi-modal neuroimaging natural history study, aims to address these shortcomings by enabling better understanding of underlying pathology and identifying sensitive, clinical trial ready, neuroimaging biomarkers for FRDA.

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Background: Individuals with Friedreich ataxia (FRDA) can find it difficult to access specialized clinical care. To facilitate best practice in delivering healthcare for FRDA, clinical management guidelines (CMGs) were developed in 2014. However, the lack of high-certainty evidence and the inadequacy of accepted metrics to measure health status continues to present challenges in FRDA and other rare diseases.

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Spinocerebellar ataxias (SCAs) are progressive neurodegenerative disorders, but there is no metric that predicts disease severity over time. We hypothesized that by developing a new metric, the Severity Factor (S-Factor) using immutable disease parameters, it would be possible to capture disease severity independent of clinical rating scales. Extracting data from the CRC-SCA and READISCA natural history studies, we calculated the S-Factor for 438 participants with symptomatic SCA1, SCA2, SCA3, or SCA6, as follows: ((length of CAG repeat expansion - maximum normal repeat length) /maximum normal repeat length) × (current age - age at disease onset) × 10).

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Article Synopsis
  • The study aims to clarify patterns of neurologic deterioration in Friedreich ataxia (FRDA), focusing on genetic diversity and age stratification to enhance future research design.
  • It analyzed data from over 1,100 participants using various clinical outcome measures and sought to differentiate disease progression based on factors like age of onset and ambulation status.
  • Findings indicate that younger patients experience more pronounced declines in function, suggesting that future clinical studies should focus on specific age groups and functional status to minimize variability and improve treatment balance.
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Background And Objectives: The goal of this work was to determine whether locally acting ACE-083 is safe and well tolerated and increases muscle volume, motor function, and quality of life (QoL) in adults with Charcot-Marie-Tooth disease (CMT) type 1.

Methods: This phase 2 study enrolled adults with CMT1 or CMTX (N = 63). Part 1 was open label and evaluated the safety and tolerability of different dose levels of ACE-083 for use in part 2.

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The purpose of this review is to describe the current diagnostic approach to inherited ataxias during childhood. With the expanding use and availability of gene testing technologies including large sequencing panels, the ability to arrive at a precise genetic diagnosis in this group of disorders has been improving. We have reviewed all the gene sequencing studies of ataxias available by a comprehensive literature search and summarize their results.

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Introduction/aims: Myotonic dystrophy type 1 (DM1) is known to affect cognitive function, but the best methods to assess central nervous system involvement in multicenter studies have not been determined. In this study our primary aim was to evaluate the potential of computerized cognitive tests to assess cognition in DM1.

Methods: We conducted a prospective, longitudinal, observational study of 113 adults with DM1 at six sites.

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Objective: The objective of this study was to characterize the incidence and progression of scoliosis in the natural history of Friedreich's ataxia (FRDA) and document the factors leading to the requirement for corrective surgery.

Methods: Data on the prevalence of scoliosis and scoliosis surgery from up to 17 years of follow-up collected during a large natural history study in FRDA (1116 patients at 4928 visits) were summarized descriptively and subjected to time to event analyses.

Results: Well over 90% of early or typical FRDA patients (as determined by age of onset) developed intermediate to severe scoliosis, while patients with a later onset (>14 years) had no or much lower prevalence of scoliosis.

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Introduction: Periodic paralysis (PP) is thought to be limited to episodes of muscle weakness, but there are reports of fibromyalgia-like pain in PP. We aimed to evaluate pain and comorbid sleep, fatigue, and mood disorders in PP patients.

Methods: We administered a cross-sectional survey to PP patients at the 2019 Periodic Paralysis Conference.

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