Preventative treatment of tuberous sclerosis complex with sirolimus: Phase I safety and efficacy results.

Objective: Tuberous sclerosis complex (TSC) results from overactivity of the mechanistic target of rapamycin (mTOR). Sirolimus and everolimus are mTOR inhibitors that treat most facets of TSC but are understudied in infants. We sought to understand the safety and potential efficacy of preventative sirolimus in infants with TSC.

Expanded-Access Use of Elamipretide Improves Quality of Life in Patients With Rare Mitochondrial Disorders Characterized by Ophthalmic Symptoms: A Case Series.

This case series presents the use of elamipretide in two patients with different progressive mitochondrial disorders (chronic progressive external ophthalmoplegia [CPEO] plus and neuropathy, ataxia, and retinitis pigmentosa [NARP] syndrome) characterized by ophthalmic traits. Elamipretide was well tolerated and both patients demonstrated improvement in symptoms while on therapy.

Genotype-specific effects of elamipretide in patients with primary mitochondrial myopathy: a post hoc analysis of the MMPOWER-3 trial.

Background: As previously published, the MMPOWER-3 clinical trial did not demonstrate a significant benefit of elamipretide treatment in a genotypically diverse population of adults with primary mitochondrial myopathy (PMM). However, the prespecified subgroup of subjects with disease-causing nuclear DNA (nDNA) pathogenic variants receiving elamipretide experienced an improvement in the six-minute walk test (6MWT), while the cohort of subjects with mitochondrial DNA (mtDNA) pathogenic variants showed no difference versus placebo. These published findings prompted additional genotype-specific post hoc analyses of the MMPOWER-3 trial.

Safety and efficacy of intra-erythrocyte dexamethasone sodium phosphate in children with ataxia telangiectasia (ATTeST): a multicentre, randomised, double-blind, placebo-controlled phase 3 trial.

Background: Ataxia telangiectasia is a multisystem disorder with progressive neurodegeneration. Corticosteroids can improve neurological functioning in patients with the disorder but adrenal suppression and symptom recurrence on treatment discontinuation has limited their use, prompting the development of novel steroid delivery systems. The aim of the ATTeST study was to evaluate the efficacy and safety of intra-erythrocyte delivery of dexamethasone sodium phosphate compared with placebo in children with ataxia telangiectasia.

Expanded-access use of elamipretide in a patient with membrane protein-associated neurodegeneration.

This case report presents a progressively declining 17-year-old patient with membrane protein-associated neurodegeneration who demonstrated symptomatic improvements in her dysarthria, dysphagia, and gait, and objective improvements in her 6-minute walk test and 5 times sit-to-stand test during elamipretide treatment.

Early Treatment with Vigabatrin Does Not Decrease Focal Seizures or Improve Cognition in Tuberous Sclerosis Complex: The PREVeNT Trial.

Objective: This study was undertaken to test the hypothesis that early vigabatrin treatment in tuberous sclerosis complex (TSC) infants improves neurocognitive outcome at 24 months of age.

Methods: A phase IIb multicenter randomized double-blind placebo-controlled trial was conducted of vigabatrin at first epileptiform electroencephalogram (EEG) versus vigabatrin at seizure onset in infants with TSC. Primary outcome was Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) cognitive assessment score at 24 months.

Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial.

Background And Objectives: Primary mitochondrial myopathies (PMMs) encompass a group of genetic disorders that impair mitochondrial oxidative phosphorylation, adversely affecting physical function, exercise capacity, and quality of life (QoL). Current PMM standards of care address symptoms, with limited clinical impact, constituting a significant therapeutic unmet need. We present data from MMPOWER-3, a pivotal, phase-3, randomized, double-blind, placebo-controlled clinical trial that evaluated the efficacy and safety of elamipretide in participants with genetically confirmed PMM.

Corrigendum to "A new pathogenic POLG variant" [Molecular Genetics and Metabolism Reports 32 (2022) 100890].

[This corrects the article DOI: 10.1016/j.ymgmr.

Use of Elamipretide in patients assigned treatment in the compassionate use program: Case series in pediatric patients with rare orphan diseases.

Several mitochondrial diseases are caused by pathogenic variants that impair membrane phospholipid remodeling, with no FDA-approved therapies. Elamipretide targets the inner mitochondrial membrane where it binds to cardiolipin, resulting in improved membrane stability, cellular respiration, and ATP production. In clinical trials, elamipretide produced clinical and functional improvements in adults and adolescents with mitochondrial disorders, such as primary mitochondrial myopathy and Barth syndrome; however, experience in younger patients is limited and to our knowledge, these are the first case reports on the safety and efficacy of elamipretide treatment in children under 12 years of age.

A new pathogenic POLG variant.

gene mutations are the most common causes of inherited mitochondrial disorders. The enzyme produced by this gene is responsible for the replication and repair of mitochondrial DNA. To date, around 300 pathogenic variants have been described in this gene.

Phenotypic and genetic spectrum of ATP6V1A encephalopathy: a disorder of lysosomal homeostasis.

Vacuolar-type H+-ATPase (V-ATPase) is a multimeric complex present in a variety of cellular membranes that acts as an ATP-dependent proton pump and plays a key role in pH homeostasis and intracellular signalling pathways. In humans, 22 autosomal genes encode for a redundant set of subunits allowing the composition of diverse V-ATPase complexes with specific properties and expression. Sixteen subunits have been linked to human disease.

NEXMIF pathogenic variants in individuals of Korean, Vietnamese, and Mexican descent.

NEXMIF pathogenic variants have been known to produce a wide spectrum of X-linked intellectual disability (ID) in both males and females. Thus far, few individuals from diverse populations have been described with NEXMIF-related disorders. Herein, we report three individuals with NEXMIF pathogenic variants, the first two are the only males of Korean and Vietnamese descent described with this disorder to our knowledge.

Heterozygous variants in SPTBN1 cause intellectual disability and autism.

Spectrins are common components of cytoskeletons, binding to cytoskeletal elements and the plasma membrane, allowing proper localization of essential membrane proteins, signal transduction, and cellular scaffolding. Spectrins are assembled from α and β subunits, encoded by SPTA1 and SPTAN1 (α) and SPTB, SPTBN1, SPTBN2, SPTBN4, and SPTBN5 (β). Pathogenic variants in various spectrin genes are associated with erythroid cell disorders (SPTA1, SPTB) and neurologic disorders (SPTAN1, SPTBN2, and SPTBN4), but no phenotypes have been definitively associated with variants in SPTBN1 or SPTBN5.

Adult phenotype of encephalopathy.

Background: Pathogenic variants are a frequent cause of developmental and epileptic encephalopathy.

Methods: We recruited 13 adults (between 18 years and 45 years of age) with encephalopathy and reviewed their clinical, EEG, neuroimaging and treatment history.

Results: While most patients had daily seizures at seizure onset, seizure frequency declined or remitted during childhood and adulthood.

Hypoglycemia in mitochondrial disorders.

Diabetes and hyperglycemia are common features of mitochondrial disorders. This study investigates the frequency of non-iatrogenic hypoglycemia in individuals with these disorders. Of 116 patients, 22 (18.

Leigh Syndrome as a Phenotype of Near-Homoplasmic m.8344 A>G Variant in Children.

In the field of mitochondrial medicine, correlation of clinical phenotype with mutation heteroplasmy remains an outstanding question with few, if any, clear thresholds corresponding to a given phenotype. The m.8344A>G mutation is most commonly associated with myoclonus epilepsy and ragged red fiber syndrome (MERRF) at varying levels of heteroplasmy.

Two different genetic etiologies for tuberous sclerosis complex (TSC) in a single family.

Background: Tuberous sclerosis complex (TSC) is an autosomal dominant genetic condition that involves abnormalities of the skin, hamartomas in the heart, brain, and kidneys, seizures, as well as TSC-associated neuropsychiatric disorders (TAND). About 90%-95% of individuals with TSC will have an identifiable pathogenic variant in either TSC1 or TSC2. We present here two family members with clinical diagnoses of TSC that were later determined to be due to two different genetic etiologies.

De novo EIF2AK1 and EIF2AK2 Variants Are Associated with Developmental Delay, Leukoencephalopathy, and Neurologic Decompensation.

EIF2AK1 and EIF2AK2 encode members of the eukaryotic translation initiation factor 2 alpha kinase (EIF2AK) family that inhibits protein synthesis in response to physiologic stress conditions. EIF2AK2 is also involved in innate immune response and the regulation of signal transduction, apoptosis, cell proliferation, and differentiation. Despite these findings, human disorders associated with deleterious variants in EIF2AK1 and EIF2AK2 have not been reported.

BAZ2B haploinsufficiency as a cause of developmental delay, intellectual disability, and autism spectrum disorder.

The bromodomain adjacent to zinc finger 2B gene (BAZ2B) encodes a protein involved in chromatin remodeling. Loss of BAZ2B function has been postulated to cause neurodevelopmental disorders. To determine whether BAZ2B deficiency is likely to contribute to the pathogenesis of these disorders, we performed bioinformatics analyses that demonstrated a high level of functional convergence during fetal cortical development between BAZ2B and genes known to cause autism spectrum disorder (ASD) and neurodevelopmental disorder.