Adeno-associated virus serotype 9 antibody titers in patients with SMA pre-screened for treatment with onasemnogene abeparvovec -routine care evidence.

Spinal muscular atrophy (SMA) is characterized by progressive weakness of skeletal and respiratory muscles. This study aimed to evaluate the prevalence of pre-existing anti adeno-associated virus serotype 9 antibody (AAV9-Ab) titers among infantile-onset SMA diagnosed infants pre-screened for treatment with AAV9-based onasemnogene abeparvovec, and to explore whether clinical and/or demographic characteristics are correlated with AAV9 Ab test results. This is a retrospective multicenter study of children diagnosed with 5q SMA younger than two years of age. The obtained data included demographic data, SMA type, SMN2 gene copy number, onset date, and results of AAV9-Ab test and of SMA prior treatments. Thirty-four patients were enrolled; six patients had positive results of AAV9-Ab (titer > 1:50) in the initial screening, 15 patients were re-tested for AAV9-Abs, of whom, three patients had seroreverted [1.5-4.5 months] between the two AAV9-Abs tests. One patient had seroconverted (5.5 months after the first AAV9-Abs test). The remaining 11 patients presented matching titer results in the two tests. No demographic/clinical factors were correlated to high AAV9-Abs titers (P > 0.05).We recommend AAV9-Ab re-tests to be performed until the age of 8 months, or, if 1.5 months or more have passed after the initial AAV9-Abs test.

Addition of galactose-1-phosphate measurement enhances newborn screening for classical galactosemia.

Galactosemia is an inborn disorder of carbohydrate metabolism of which early detection can prevent severe illness. Although the assay for galactose-1-phosphate uridyltransferase (GALT) enzyme activity has been available since the 1960s, many issues prevented it from becoming universal. In order to develop the Israeli newborn screening pilot algorithm for galactosemia, flow injection analysis tandem mass spectrometry measurement of galactose-1-phosphate in archived dried blood spots from newborns with classical galactosemia, galactosemia variants, epimerase deficiency, and normal controls, was conducted. Out of 431 330 newborns screened during the pilot study (30 months), two with classical galactosemia and four with epimerase deficiency were identified and confirmed. Five false positives and no false negatives were recorded. Following this pilot study, the Israeli final and routine newborn screening algorithm, as recommended by the Advisory Committee to the National Newborn Screening Program, now consists of galactose-1-phosphate measurement integrated into the routine tandem mass spectrometry panel as the first-tier screening test, and GALT enzyme activity as the second-tier performed to identify only newborns suspected to be at risk for classical galactosemia. The GALT enzyme activity cut-off used in the final algorithm was lowered in order to avoid false positives.

Predictors of disease course and long-term outcomes of idiopathic intracranial hypertension in children and adolescents.

This study aimed to identify predictors for unfavorable disease course and clinical and visual outcomes in pediatric patients with idiopathic intracranial hypertension (IIH). Employing a multi-tiered approach, we retrospectively analyzed clinical, ophthalmic, and neuroimaging data from patients diagnosed with IIH between 2003 and 2021. Of the 97 patients included, 56 (58%) were females. The median age was 12 years [Interquartile range (IQR) 9, 14], and the median follow-up time was 39.0 months (IQR 14.8, 90.9). Forty-two (43%) patients had an unfavorable disease course, 28 (29%) had persistence of headache at last follow-up, and 16 (18%) had a poor visual outcome, most of them with mild visual disturbances. Poor visual outcome was more common in females compared to males [16/47 (34%) vs. 0/39, p < 0.001)]. On multivariate regression analysis, female sex and disease recurrence were significantly associated with poor visual outcomes (OR: 18.5, CI:1.3-270, P = 0.03, and OR: 5.1, CI: 1.2-22.5, P = 0.03, respectively). Patients with persistent headaches exhibited lower incidence of papilledema, lower opening pressure, and fewer neuroimaging markers indicating elevated intracranial pressure. CONCLUSIONS: This study provides insights into predictive factors for an unfavorable disease course, persistent headaches, and poor visual outcomes in patients with childhood IIH. Patients with persistent headaches may have a variant of a chronic pain syndrome warranting a different therapeutic approach. WHAT IS KNOWN: • Childhood-onset Idiopathic Intracranial hypertension (IIH) is a heterogenous disease. The knowledge on disease trajectory and long-term outcomes and its predictors is limited. WHAT IS NEW: • A higher opening pressure and factors suggestive of the metabolic syndrome predict an unfavorable disease course whereas female sex and disease recurrence are significantly associated with poor visual outcomes • A third of the patients diagnosed with IIH experience ongoing headaches despite achieving favorable visual outcomes. This subset, characterized by lower disease-severity indicators at onset may represent a distinct subgroup warranting a different therapeutic approach.

Neurosurgical aspects of Noonan syndrome.

PURPOSE: Noonan syndrome (NS) is a rare neurodevelopmental syndrome characterized by dysmorphic features, congenital heart defects, neurodevelopmental delay, and bleeding diathesis. Though rare, several neurosurgical manifestations have been associated with NS, such as Chiari malformation (CM-I), syringomyelia, brain tumors, moyamoya, and craniosynostosis. We describe our experience in treating children with NS and various neurosurgical conditions, and review the current literature on neurosurgical aspects of NS. METHODS: Data were retrospectively collected from the medical records of children with NS who were operated at a tertiary pediatric neurosurgery department, between 2014 and 2021. Inclusion criteria were clinical or genetic diagnosis of NS, age < 18 years at treatment, and need for a neurosurgical intervention of any kind. RESULTS: Five cases fulfilled the inclusion criteria. Two had tumors, one underwent surgical resection. Three had CM-I, syringomyelia, and hydrocephalus, of whom one also had craniosynostosis. Comorbidities included pulmonary stenosis in two patients and hypertrophic cardiomyopathy in one. Three patients had bleeding diathesis, two of them with abnormal coagulation tests. Four patients were treated preoperatively with tranexamic acid, and two with Von Willebrand factor or platelets (1 each). One patient with a clinical bleeding predisposition developed hematomyelia following a syringe-subarachnoid shunt revision. CONCLUSIONS: NS is associated with a spectrum of central nervous system abnormalities, some of which with known etiology, while in others a pathophysiological mechanism has been suggested in the literature. When operating on a child with NS, a meticulous anesthetic, hematologic, and cardiac evaluation should be conducted. Neurosurgical interventions should then be planned accordingly.

Group comprehensive behavioral intervention for tics contribution to broader cognitive and emotion regulation in children.

There is increasing evidence for the effectiveness of behavioral techniques in managing tics in youth with Tourette syndrome and tics disorders (TDs). One such intervention is Comprehensive Behavioral Intervention for Tics (CBIT), which focuses on reducing tic severity by training control and regulation. In view of the regulation deficits characteristic to TDs, in the current study, we aimed to explore the contribution of CBIT beyond tic control, to a wider expression of regulation abilities-cognitive inhibition and emotion regulation. A total of 55 participants with TDs, aged 8-15, who were randomly assigned to group-CBIT or group-Educational Intervention for Tics, were compared on cognitive inhibition tests and use of emotion-regulation strategies, pre- and post-intervention. Whereas on none of the scales a significant interaction effect was found reflecting superiority of CBIT over EIT, repeated measures ANOVA revealed a significant time effect, with post hoc analyses indicating that cognitive inhibition and cognitive reappraisal significantly increased following CBIT intervention only. Within the group-CBIT, the increase in cognitive reappraisal was associated with higher intellectual ability. These findings may lead to a broader understanding of CBIT contribution to more than tic control, but rather to better cognitive and emotional regulation abilities.

Monogenic Causes of Apparently Idiopathic Perinatal Intracranial Hemorrhage.

OBJECTIVE: Perinatal intracranial hemorrhage (pICH) is a rare event that occurs during the fetal/neonatal period with potentially devastating neurological outcome. However, the etiology of pICH is frequently hard to depict. We investigated the role of rare genetic variations in unexplained cases of pICH. METHODS: We performed whole-exome sequencing (WES) in fetuses and term neonates with otherwise unexplained pICH and their parents. Variant causality was determined according to the American College of Medical Genetics and Genomics (ACMG) criteria, consistency between suggested genes and phenotypes, and mode of inheritance. RESULTS: Twenty-six probands (25 families) were included in the study (9 with a prenatal diagnosis and 17 with a postnatal diagnosis). Intraventricular hemorrhage (IVH) was the most common type of hemorrhage (n = 16, 62%), followed by subpial (n = 4, 15%), subdural (n = 4, 15%), and parenchymal (n = 2, 8%) hemorrhage. Causative/likely causative variants were found in 4 subjects from 3 of the 25 families (12%) involving genes related to the brain microenvironment (COL4A1, COL4A2, and TREX-1). Additionally, potentially causative variants were detected in genes related to coagulation (GP1BA, F11, Von Willebrand factor [VWF], FGA, and F7; n = 4, 16%). A potential candidate gene for phenotypic expansion related to microtubular function (DNAH5) was identified in 1 case (4%). Fifty-five percent of the variants were inherited from an asymptomatic parent. Overall, these findings showed a monogenic cause for pICH in 12% to 32% of the families. INTERPRETATION: Our findings reveal a clinically significant diagnostic yield of WES in apparently idiopathic pICH and support the use of WES in the evaluation of these cases. ANN NEUROL 2021;89:813-822.

Radiologically isolated aquaporin-4 antibody neuromyelitis optica spectrum disorder.

Aquaporin-4 antibody (AQP4-Ab) Neuromyelitis Optica Spectrum Disorder (NMOSD) is a rare neuroinflammatory syndrome presenting predominantly with optic neuritis and transverse myelitis. We report a case of radiologically isolated longitudinally extensive optic neuritis in an asymptomatic 12-year-old female with positive serum AQP4-Ab, with resolution of imaging changes after immune therapy. By contrast to patients with radiologically isolated syndrome, of which some will never convert to multiple sclerosis, the pathogenicity of AQP4-Ab in the context of sub-clinical disease, supported treatment in our patient. Given the severe morbidity in AQP4-Ab NMOSD, prognostic biomarkers for disease severity are required to guide optimal therapy for patients.

Cerebrospinal fluid characteristics of patients treated with intrathecal nusinersen for spinal muscular atrophy.

INTRODUCTION/AIMS: There is limited information on the potential effects of repeated intrathecal antisense oligonucleotide drug delivery on cerebrospinal fluid (CSF) biochemical and blood cell profiles. This study aimed to examine longitudinal changes in the biochemical components (glucose, protein) and blood cell counts in the CSF of spinal muscular atrophy (SMA) patients treated with intrathecal nusinersen. METHODS: We collected and analyzed clinical and CSF parameters (cell count, protein, glucose, culture) of 50 individuals with SMA during nusinersen treatment (22 type 1, 17 type 2, and 11 type 3). RESULTS: The median protein concentration at baseline and during treatment was within the normal range but rose during treatment and was significantly above baseline at the time of the ninth intrathecal injection (p = 0.02, two-tailed Wilcoxon matched-pairs test, and p = 0.0015, Friedman test for repeated measures). Further analysis showed that the increase in CSF protein concentration was evident for SMA types 2 and 3 patients, but not for type 1. This observation was also demonstrated by a significant correlation between the SMN2 gene copy number and the increase in CSF protein concentration (Spearman rank correlation test). DISCUSSION: Our results demonstrate that a delayed increase in CSF protein concentration is expected during nusinersen treatment for SMA types 2 and 3. This might reflect the medication's effect and a possible therapeutic biochemical marker.

Muscle microRNAs in the cerebrospinal fluid predict clinical response to nusinersen therapy in type II and type III spinal muscular atrophy patients.

BACKGROUND AND PURPOSE: The antisense oligonucleotide nusinersen (Spinraza) regulates splicing of the survival motor neuron 2 (SMN2) messenger RNA to increase SMN protein expression. Nusinersen has improved ventilator-free survival and motor function outcomes in infantile onset forms of spinal muscular atrophy (SMA), treated early in the course of the disease. However, the response in later onset forms of SMA is highly variable and dependent on symptom severity and disease duration at treatment initiation. Therefore, we aimed to identify novel noninvasive biomarkers that could predict the response to nusinersen in type II and III SMA patients. METHODS: Thirty-four SMA patients were included. We applied next generation sequencing to identify microRNAs in the cerebrospinal fluid (CSF) as candidate biomarkers predicting response to nusinersen. Hammersmith Functional Motor Scale Expanded (HFMSE) was conducted at baseline and 6 months after initiation of nusinersen therapy to assess motor function. Patients changing by ≥3 or ≤0 points in the HFMSE total score were considered to be responders or nonresponders, respectively. RESULTS: Lower baseline levels of two muscle microRNAs (miR-206 and miR-133a-3p), alone or in combination, predicted the clinical response to nusinersen after 6 months of therapy. Moreover, miR-206 levels were inversely correlated with the HFMSE score. CONCLUSIONS: Lower miR-206 and miR-133a-3p in the CSF predict more robust clinical response to nusinersen treatment in later onset SMA patients. These novel findings have high clinical relevance for identifying early treatment response to nusinersen in later onset SMA patients and call for testing the ability of miRNAs to predict more sustained long-term benefit.

Group behavioral interventions for tics and comorbid symptoms in children with chronic tic disorders.

Exposure and Response Prevention (ERP), Habit Reversal Training (HRT) and Comprehensive Behavioral Intervention for Tics (CBIT) are effective in reducing tic severity. ERP and HRT have recently gained primary support in a group setting, while CBIT has not been examined similarly. We compared the efficacy of group-CBIT to group-Educational Intervention for Tics (group-EIT) for tics and comorbid symptoms. Children with Tourette Syndrome (TS) or Chronic Tic Disorder (CTD) were randomized to group-CBIT or group-EIT. Tics and comorbid symptoms were assessed in forty-six children pre- and postintervention, and 3-month later. Yale Global Tic Severity Scale (YGTSS) Motor tic severity decreased following both interventions, and was maintained at follow-up for group-CBIT only. The Parent Tic Questionnaire (PTQ) showed significant decrease in total and motor tic severity following group-CBIT only, a gain maintained three months later. YGTSS impairment score decreased following both interventions and was maintained at follow-up. YGTSS vocal tic severity score increased following both interventions, and then decreased significantly at follow up. Co-morbid symptoms including anxiety, behavioral problems, and aggressive behavior decreased following both interventions. Children with behavioral problems benefitted less while children with higher intellectual ability benefit more from intervention. Both group interventions showed efficacy in reducing tic impairment and comorbid symptoms. Group-CBIT was superior to group-EIT in reducing motor tic severity at 3-month follow-up, showing an advantage for tic-focused treatment. Based on the PTQ, group-CBIT was superior to group-EIT in reducing motor, vocal, and total tic scores, a gain maintained three months later. Clinical trial registry information-Group Intervention for Children with Chronic Tics Syndrome: CBIT vs Psychoeducational Intervention URL: http://clinicaltrials.gov , Identifier: NCT02407951, http://www.controlled-trials.com ).

The role of orotic acid measurement in routine newborn screening for urea cycle disorders.

Urea cycle disorders (UCDs), including OTC deficiency (OTCD), are life-threatening diseases with a broad clinical spectrum. Early diagnosis and initiation of treatment based on a newborn screening (NBS) test for OTCD with high specificity and sensitivity may contribute to reduction of the significant complications and high mortality. The efficacy of incorporating orotic acid determination into routine NBS was evaluated. Combined measurement of orotic acid and citrulline in archived dried blood spots from newborns with urea cycle disorders and normal controls was used to develop an algorithm for routine NBS for OTCD in Israel. Clinical information and genetic confirmation results were obtained from the follow-up care providers. About 1147986 newborns underwent routine NBS including orotic acid determination, 25 of whom were ultimately diagnosed with a UCD. Of 11 newborns with OTCD, orotate was elevated in seven but normal in two males with early-onset and two males with late-onset disease. Orotate was also elevated in archived dried blood spots of all seven retrospectively tested historical OTCD patients, only three of whom had originally been identified by NBS with low citrulline and elevated glutamine. Among the other UCDs emerge, three CPS1D cases and additional three retrospective CPS1D cases otherwise reported as a very rare condition. Combined levels of orotic acid and citrulline in routine NBS can enhance the detection of UCD, especially increasing the screening sensitivity for OTCD and differentiate it from CPS1D. Our data and the negligible extra cost for orotic acid determination might contribute to the discussion on screening for proximal UCDs in routine NBS.

Variable Genotype-Phenotype Correlation of Pompe's Disease Caused by a c.2015 G > A (p.Arg672Gln) Mutation in the GAA Gene.

Pompe's disease occurs due to an autosomal recessive trait resulting from numerous distinctive mutations in the GAA gene. It manifests as a broad spectrum of clinical phenotypes with progressive weakness that impairs motor and respiratory functions being common for all its forms. Cardiac hypertrophy is a prominent feature of its classic infantile form. To date, the pathogenic variant c.2015G > A (p.Arg672Gln) in exon 14 of the GAA gene has been described in 10 children of different ethnic groups, with variable phenotypic presentations. This work describes three children from two unrelated families of Arab ethnicity who presented with infantile-onset Pompe's disease as a result of a c.2015G > A (p.Arg672Gln) mutation. The clinical course of the children we report was more severe than previous reports. This further emphasizes the lack of a strict genotype-phenotype correlation in regard to the unique c.2015G > A (p.R672Q) mutation that causes Pompe's disease. This information contributes to the knowledge of the phenotypic expression of the specific mutation c.2015G > A (p.Arg672Gln) that causes Pompe's disease.

Nutritional Therapy in Children With Spinal Muscular Atrophy in the Era of Nusinersen.

OBJECTIVES: Spinal muscular atrophy (SMA) is a genetic motor neuron disorder characterized by progressive muscle atrophy. Our aims were to evaluate the impact of nutritional intervention and nusinersen therapy on the nutritional status of SMA patients. STUDY DESIGN: This prospective study included all children and young adults (<24 years of age) with SMA who attended our multidisciplinary SMA clinic, during January 2017-July 2019. We documented demographic, clinical, anthropometric, and nutritional data at baseline and follow-up. A nutritional intervention was implemented according to standards of the 2018 Consensus Statement of SMA Management. RESULTS: The cohort included 51 SMA patients with a median age of 7.2 (interquartile range 2.1-15.3) years. Among them, 24 (47%) were SMA type 1, 16 (31.4%) SMA type 2, and 11 (21.6%) SMA type 3 patients. At baseline, 28 (54.9%) patients presented with malnutrition, 20 (71.4%) of whom with severe malnutrition. A decline in the frequency of severe malnutrition of SMA type 1 patients was observed at follow-up. The body mass index of patients who started nusinersen therapy after the nutritional intervention increased significantly compared with patients that started nusinersen therapy before the nutritional intervention (P = 0.042). There was also a significant increase in total energy and protein consumption in the former group (P = 0.043). CONCLUSIONS: Malnutrition is frequent among children with SMA, and the nutritional status of patients that started nusinersen therapy after implementation of a nutritional intervention underwent a more significant improvement. The importance of combining adequate nutritional management with disease-modifying treatment is highlighted.

Neurodevelopmental outcome of children born with an isolated atretic cephalocele.

PURPOSE: The existing data on the neurodevelopmental outcome of children born with an isolated atretic cephalocele (IAC) are scant. We aimed to expand upon these data by describing our experience with affected children, as well as assist parents and clinicians in deciding how to proceed when an IAC is diagnosed prenatally. METHODS: A follow-up study was conducted on nine children who were born with an IAC. Evaluations were performed by pediatric neurologists and child development specialists. Developmental outcomes were based on a global development evaluation that assessed gross and fine motor skills, receptive and expressive language levels, activities of daily living, communication skills, and social domains. Adaptive skills were estimated by the Adaptive Behavior Assessment System, Second Edition. RESULTS: None of the nine children (median age 4 years and 6 months) had abnormal findings on neurological examination. Six children had age-appropriate developmental milestones, two had a mild motor delay, and one had mild expressive language delay (catchup was achieved by all of the latter three by ~ 3.5 years of age). The mean general adaptive composite score was 105 ± 11.7 (normal = 100). None of the children had behavioral, social, or communication problems. CONCLUSIONS: Children diagnosed with an IAC with/without a falcine sinus and devoid of coexisting intracranial abnormalities seem to have a normal neurodevelopmental outcome. Continuation of pregnancy may be recommended when an IAC is detected prenatally, and reassurance if detected postnatally.

Genetic landscape of Rett syndrome-like phenotypes revealed by whole exome sequencing.

BACKGROUND: Rett syndrome (RTT) is a characteristic neurological disease presenting with regressive loss of neurodevelopmental milestones. Typical RTT is generally caused by abnormality of methyl-CpG binding protein 2 (MECP2). Our objective to investigate the genetic landscape of MECP2-negative typical/atypical RTT and RTT-like phenotypes using whole exome sequencing (WES). METHODS: We performed WES on 77 MECP2-negative patients either with typical RTT (n=11), atypical RTT (n=22) or RTT-like phenotypes (n=44) incompatible with the RTT criteria. RESULTS: Pathogenic or likely pathogenic single-nucleotide variants in 28 known genes were found in 39 of 77 (50.6%) patients. WES-based CNV analysis revealed pathogenic deletions involving six known genes (including MECP2) in 8 of 77 (10.4%) patients. Overall, diagnostic yield was 47 of 77 (61.0 %). Furthermore, strong candidate variants were found in four novel genes: a de novo variant in each of ATPase H+ transporting V0 subunit A1 (ATP6V0A1), ubiquitin-specific peptidase 8 (USP8) and microtubule-associated serine/threonine kinase 3 (MAST3), as well as biallelic variants in nuclear receptor corepressor 2 (NCOR2). CONCLUSIONS: Our study provides a new landscape including additional genetic variants contributing to RTT-like phenotypes, highlighting the importance of comprehensive genetic analysis.

Medical treatment of tuberous sclerosis-related epilepsy.

Epilepsy is one of the most frequent CNS manifestations of tuberous sclerosis, and for most patients, it is the major debilitating factor. In up to 70% of the cases, the epilepsy is refractory and usually associated with significant behavioral as well as developmental consequences. Therefore, controlling seizures is one of the biggest medical and surgical challenges. Understanding the cellular mechanism involved in the disease empowered targeted research aimed toward early intervention in the epileptogenicity process. In this review, we present an update on the pharmacological treatments in tuberous sclerosis-related epilepsy.

VPS53 gene is associated with a new phenotype of complicated hereditary spastic paraparesis.

Hereditary spastic paraparesis (HSP) is a progressive neurodegenerative disorder, characterized by progressive lower limb weakness and spasticity. Multiple genes are associated with both the pure and complicated HSP types. Our study is aimed at seeking for novel genetic basis of HSP in a family with two affected siblings. Genetic analysis using whole exome sequencing was conducted in a family quartet with two female siblings, who presented with complicated HSP featuring slowly progressive paraparesis, mild-moderate intellectual disability, normal head circumference (HC), and normal magnetic resonance imaging (MRI). A homozygous pathogenic variant was identified in both siblings in the VPS53 gene (c.2084A>G: c.2084A>G, p.Gln695Arg). This gene acts as a component of the Golgi-associated retrograde protein (GARP) complex that is involved, among others, in intracellular cholesterol transport and sphingolipid homeostasis in lysosomes and was previously associated with progressive cerebello-cerebral atrophy (PCCA) type 2. This is the first description of the VPS53 gene as a cause of autosomal recessive complicated HSP. Lysosomal dysfunction as a result of impaired cholesterol trafficking can explain the neurodegenerative processes responsible for the HSP. Our finding expands the phenotype of VPS53-related disease and warrants the addition of VPS53 analysis to the genetic investigation in patients with autosomal recessive HSP. The exact role of GARP complex in neurodegenerative processes should be further elucidated.

Biallelic TBCD Mutations Cause Early-Onset Neurodegenerative Encephalopathy.

We describe four families with affected siblings showing unique clinical features: early-onset (before 1 year of age) progressive diffuse brain atrophy with regression, postnatal microcephaly, postnatal growth retardation, muscle weakness/atrophy, and respiratory failure. By whole-exome sequencing, we identified biallelic TBCD mutations in eight affected individuals from the four families. TBCD encodes TBCD (tubulin folding co-factor D), which is one of five tubulin-specific chaperones playing a pivotal role in microtubule assembly in all cells. A total of seven mutations were found: five missense mutations, one nonsense, and one splice site mutation resulting in a frameshift. In vitro cell experiments revealed the impaired binding between most mutant TBCD proteins and ARL2, TBCE, and ß-tubulin. The in vivo experiments using olfactory projection neurons in Drosophila melanogaster indicated that the TBCD mutations caused loss of function. The wide range of clinical severity seen in this neurodegenerative encephalopathy may result from the residual function of mutant TBCD proteins. Furthermore, the autopsied brain from one deceased individual showed characteristic neurodegenerative findings: cactus and somatic sprout formations in the residual Purkinje cells in the cerebellum, which are also seen in some diseases associated with mitochondrial impairment. Defects of microtubule formation caused by TBCD mutations may underlie the pathomechanism of this neurodegenerative encephalopathy.

Recurrent De Novo Dominant Mutations in SLC25A4 Cause Severe Early-Onset Mitochondrial Disease and Loss of Mitochondrial DNA Copy Number.

Mutations in SLC25A4 encoding the mitochondrial ADP/ATP carrier AAC1 are well-recognized causes of mitochondrial disease. Several heterozygous SLC25A4 mutations cause adult-onset autosomal-dominant progressive external ophthalmoplegia associated with multiple mitochondrial DNA deletions, whereas recessive SLC25A4 mutations cause childhood-onset mitochondrial myopathy and cardiomyopathy. Here, we describe the identification by whole-exome sequencing of seven probands harboring dominant, de novo SLC25A4 mutations. All affected individuals presented at birth, were ventilator dependent and, where tested, revealed severe combined mitochondrial respiratory chain deficiencies associated with a marked loss of mitochondrial DNA copy number in skeletal muscle. Strikingly, an identical c.239G>A (p.Arg80His) mutation was present in four of the seven subjects, and the other three case subjects harbored the same c.703C>G (p.Arg235Gly) mutation. Analysis of skeletal muscle revealed a marked decrease of AAC1 protein levels and loss of respiratory chain complexes containing mitochondrial DNA-encoded subunits. We show that both recombinant AAC1 mutant proteins are severely impaired in ADP/ATP transport, affecting most likely the substrate binding and mechanics of the carrier, respectively. This highly reduced capacity for transport probably affects mitochondrial DNA maintenance and in turn respiration, causing a severe energy crisis. The confirmation of the pathogenicity of these de novo SLC25A4 mutations highlights a third distinct clinical phenotype associated with mutation of this gene and demonstrates that early-onset mitochondrial disease can be caused by recurrent de novo mutations, which has significant implications for the application and analysis of whole-exome sequencing data in mitochondrial disease.

The safety, tolerability, and effectiveness of PTL-101, an oral cannabidiol formulation, in pediatric intractable epilepsy: A phase II, open-label, single-center study.

INTRODUCTION: Several works have reported on the antiepileptic impact of cannabis-based preparations in patients with treatment-resistant epilepsy (TRE). However, current formulations suffer from low bioavailability and side effects. PTL-101, an oral formulation containing highly purified cannabidiol (CBD) embedded in seamless gelatin matrix beadlets was designed to enhance bioavailability and maintain a constant gastrointestinal transit time. METHODS: This phase II, prospective study was open to pediatric patients with TRE on stable antiepileptic drugs' (AEDs) doses, who experienced ≥4 seizures within four weeks of enrolment and with a history of ≥4 AEDs failing to provide seizure control. Following a 4-week observation period, patients began a 2-week dose-titration phase (up to ≤25mg/kg or 450mg, the lower of the two), followed by a 10-week maintenance treatment period. Caregivers recorded seizure frequency, type, and severity and ranked their global impressions after 7 and 12weeks of treatment. Responders were those showing a ≥50% reduction from baseline monthly seizure frequency. Safety assessments monitored vital signs, adverse effects, physical and neurological exams, and laboratory tests. RESULTS: Sixteen patients (age: 9.1±3.4) enrolled in the study; 11 completed the full treatment program. The average maintenance dose was 13.6±4.2mg/kg. Patient adherence to treatment regimens was 96.3±9.9%. By the end of the treatment period, 81.9% and 73.4±24.6% (p<0.05) reductions from baseline median seizure count and monthly seizure frequency, respectively, were recorded. Responders' rate was 56%; two patients became fully seizure-free. By study end, 8 (73%) caregivers reported an improved/very much improved condition, and 9 (82%) reported reduced/very much reduced seizure severity. Most commonly reported treatment-related adverse effects were sleep disturbance/insomnia, (4 (25.0%) patients), followed by somnolence, increased seizure frequency, and restlessness (3 patients each (18.8%)). None were serious or severe, and all resolved. CONCLUSIONS: PTL-101 was safe and tolerable for use and demonstrated a potent seizure-reducing effect among pediatric patients with TRE.