Gene replacement therapies for inherited disorders of neurotransmission: Current progress in succinic semialdehyde dehydrogenase deficiency.

Neurodevelopment is a highly organized and complex process involving lasting and often irreversible changes in the central nervous system. Inherited disorders of neurotransmission (IDNT) are a group of genetic disorders where neurotransmission is primarily affected, resulting in abnormal brain development from early life, manifest as neurodevelopmental disorders and other chronic conditions. In principle, IDNT (particularly those of monogenic causes) are amenable to gene replacement therapy via precise genetic correction. However, practical challenges for gene replacement therapy remain major hurdles for its translation from bench to bedside. We discuss key considerations for the development of gene replacement therapies for IDNT. As an example, we describe our ongoing work on gene replacement therapy for succinic semialdehyde dehydrogenase deficiency, a GABA catabolic disorder.

Autoimmune encephalitis in Israeli children - A retrospective nationwide study.

Immune-mediated or autoimmune encephalitis (AE) is a relatively new, rare and elusive form of encephalitis in children. We retrospectively collected seropositive children (0-18 years old) with well characterized antibodies through 3 reference laboratories in Israel. Clinical symptoms, MRI and EEG findings and treatment courses were described. A total of 16 patients were included in the study, with 10 females. Anti NMDA encephalitis was most common followed by anti HU and anti mGLuR1. Psychiatric symptoms, abnormal movements, seizures and behavioral changes were the most common presentation. Pathological MRI and EEG findings were described in 37% and 56% of children, respectively. Treatment with corticosteroids, Intravenous immunoglobulins (IVIG) was first line in most children. Following inadequate response children were treated with plasmapheresis and/or rituximab. Two patients relapsed following both first and second line protocols. In terms of long term prognosis, 9 children (56%) had one or more residual behavioral, psychiatric or neurologic findings. Three children required hospitalization for rehabilitation. AE remains a rare diagnosis with variable presenting symptoms, requiring a high index of suspicion. Consensus recommended treatment is generally effective in the pediatric population. Female gender was associated with a higher chance of severe disease. Larger cohorts would be needed to identify prognostic factors in the pediatric population.

Treatable inherited metabolic epilepsies.

Inherited metabolic epilepsies (IMEs) represent inherited metabolic disorders predominately presenting with seizures. While most IMEs are currently managed with symptomatic and supportive therapies, some are amenable to disorder-specific targeted treatments. In most cases, these treatments are effective only if given in a narrow time window early in the lives of affected patients. Hence, prompt recognition of treatable inherited metabolic epilepsies at an early age and as soon as symptoms appear has paramount importance. Herein, we provide an overview of inherited metabolic epilepsies, which presently have established targeted treatments showing clinical efficacy in reducing seizure burden and improving neurodevelopmental outcomes. These therapeutic modalities range from specific diets, vitamins, and supplementation of organic compounds to synthetic pharmacological agents and novel genetic-based therapies that alter the biochemical pathways of these disorders at the cellular or molecular level, steering them to their normal function.

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.

Clinical and biochemical footprints of inherited metabolic diseases. XV. Epilepsies.

We provide a comprehensive overview of inherited metabolic disorders (IMDs) in which epilepsy is a prominent manifestation. Our unique database search has identified 256 IMDs associated with various types of epilepsies, which we classified according to the classic pathophysiology-based classification of IMDs, and according to selected seizure-related factors (neonatal seizures, infantile spasms, myoclonic seizures, and characteristic EEG patterns) and treatability for the underlying metabolic defect. Our findings indicate that inherited metabolic epilepsies are more likely to present in the neonatal period, with infantile spasms or myoclonic seizures. Additionally, the ∼20% of treatable inherited metabolic epilepsies found by our search were mainly associated with the IMD groups of "cofactor and mineral metabolism" and "Intermediary nutrient metabolism." The information provided by this study, including a comprehensive list of IMDs with epilepsy stratified according to age of onset, and seizure type and characteristics, along with an overview of the key clinical features and proposed diagnostic and therapeutic approaches, may benefit any epileptologist and healthcare provider caring for individuals with metabolic conditions.

Phenotypic Correlates of Structural and Functional Protein Impairments Resultant from ALDH5A1 Variants.

Objective: To investigate the genotype-to-protein-to-phenotype correlations of succinic semialdehyde dehydrogenase deficiency (SSADHD), an inherited metabolic disorder of γ-aminobutyric acid catabolism. Methods: Bioinformatics and in silico mutagenesis analyses of ALDH5A1 variants were performed to evaluate their impact on protein stability, active site and co-factor binding domains, splicing, and homotetramer formation. Protein abnormalities were then correlated with a validated disease-specific clinical severity score and neurological, neuropsychological, biochemical, neuroimaging, and neurophysiological metrics. Results: A total of 58 individuals (1:1 male/female ratio) were affected by 32 ALDH5A1 pathogenic variants, eight of which were novel. Compared to individuals with single homotetrameric or multiple homo and heterotetrameric proteins, those predicted not to synthesize any functional enzyme protein had significantly lower expression of ALDH5A1 (p = 0.001), worse overall clinical outcomes (p = 0.008) and specifically more severe cognitive deficits (p = 0.01), epilepsy (p = 0.04) and psychiatric morbidity (p = 0.04). Compared to individuals with predictions of having no protein or a protein impaired in catalytic functions, subjects whose proteins were predicted to be impaired in stability, folding, or oligomerization had a better overall clinical outcome (p = 0.02) and adaptive skills (p = 0.04). Conclusions: The quantity and type of enzyme proteins (no protein, single homotetramers, or multiple homo and heterotetramers), as well as their structural and functional impairments (catalytic or stability, folding, or oligomerization), contribute to phenotype severity in SSADHD. These findings are valuable for assessment of disease prognosis and management, including patient selection for gene replacement therapy. Furthermore, they provide a roadmap to determine genotype-to-protein-to-phenotype relationships in other autosomal recessive disorders.

Eruption of urticaria and angioedema induced by binging and purging in an anorexia nervosa patient.

BACKGROUND: Anorexia nervosa is a perplexing psycho-biological disorder with a systemic nature, which can present in almost every organ and system of the body. Among the different presentations of starvation, several immunological and dermatological manifestations have been documented. To the best of our knowledge the occurrence of urticaria and angioedema in patients with binge or purge behaviors has yet to be documented. CASE PRESENTATION: We present a 16-year-old female patient diagnosed with anorexia nervosa binge/purge type, who presented with urticaria and angioedema shortly after binge/purge episodes that subsided when these behaviors ceased. Other possible causes for the urticaria were ruled out. DISCUSSION: This finding may represent a form of inducible urticaria, exacerbated in low-weight patients by the occurrence of binge/purge behaviors. We wish to report this observation in an attempt to widen the scope of the physical signs that may accompany eating disorders and bring this specific phenomenon into awareness. © 2016 Wiley Periodicals, Inc. (Int J Eat Disord 2016; 49:822-825).