Succinic semialdehyde dehydrogenase deficiency: in vitro and in silico characterization of a novel pathogenic missense variant and analysis of the mutational spectrum of ALDH5A1

Succinic semialdehyde dehydrogenase deficiency (SSADHD) is a rare, monogenic disorder affecting the degradation of the main inhibitory neurotransmitter \u3b3-amino butyric acid (GABA). Pathogenic variants in the ALDH5A1 gene that cause an enzymatic dysfunction of succinic semialdehyde dehydrogenase (SSADH) lead to an accumulation of potentially toxic metabolites, including \u3b3-hydroxybutyrate (GHB). Here, we present a patient with a severe phenotype of SSADHD caused by a novel genetic variant c.728T > C that leads to an exchange of leucine to proline at residue 243, located within the highly conserved nicotinamide adenine dinucleotide (NAD)+ binding domain of SSADH. Proline harbors a pyrrolidine within its side chain known for its conformational rigidity and disruption of protein secondary structures. We investigate the effect of this novel variant in vivo, in vitro, and in silico. We furthermore examine the mutational spectrum of all previously described disease-causing variants and computationally assess all biologically possible missense variants of ALDH5A1 to identify mutational hotspots

Die intrazerebrale Gentherapie des Aromatischen-L-Aminosäure-Decarboxylase-Mangels mit Eladocagene exuparvovec : Eine Stellungnahme der Gesellschaft für Neuropädiatrie (GNP), der Arbeitsgemeinschaft pädiatrischer Stoffwechselstörungen (APS), der Deutschen Gesellschaft für Neurochirurgie (DGNC) und der Deutschen Gesellschaft für Kinder- und Jugendmedizin (DGKJ)

Background The autosomal recessive defect of aromatic L‑amino acid decarboxylase (AADC) causes a severe combined deficiency of dopamine, serotonin and catecholamines. The clinical picture is characterized by truncal hypotonia, delayed or absent achievement of motor milestones, and oculogyric crises from infancy onwards. The response to conventional drug treatment is very limited, especially in severe cases. The intracerebral application of eladocagene exuparvovec, an AAV2-based gene therapy, which is expected to be approved in mid-2021, is the first available causal therapeutic approach. Aim In collaboration with the German Society of Neuropediatrics (GNP), the Working Group of Pediatric Metabolic Disorders (APS), the German Society of Neurosurgery (DGNC) and the German Society of Pediatrics and Adolescent Medicine (DGKJ), the structural requirements and practical aspects in the preparation, implementation and follow-up of the treatment with eladocagene exuparvovec were elaborated. Discussion The present statement compiles the necessary framework conditions for a quality-assured administration of eladocagene exuparvovec. The treatment requires prehospital, inpatient and posthospital care by a multiprofessional team in a specialized and qualified treatment center. Patient follow-up is intended to contribute to knowledge-generating care. Due to lack of data on the therapeutic (long-term) effect as well as on advantages and disadvantages of the different stereotactic approaches, a structured follow-up plan and documentation in an appropriate, industry-independent registry are necessary.Hintergrund Der autosomal-rezessiv vererbte Defekt der aromatischen L‑Aminosäure-Decarboxylase (AADC) führt zu einem ausgeprägten, kombinierten Mangel an Dopamin, Serotonin und Katecholaminen. Das klinische Bild ist charakterisiert durch eine rumpfbetonte, muskuläre Hypotonie, verzögertes oder fehlendes Erreichen der motorischen Meilensteine und okulogyre Krisen ab dem Säuglingsalter. Der Erfolg der konventionellen, medikamentösen Behandlung ist besonders bei schweren Verläufen sehr limitiert. Mit der intrazerebralen Applikation von Eladocagene exuparvovec (Upstaza®), einer AAV2-basierten Gentherapie, deren Zulassung für Mitte 2021 erwartet wird, steht erstmals ein kausaler Therapieansatz zur Verfügung. Ziel In Zusammenarbeit mit der Gesellschaft für Neuropädiatrie (GNP), der Arbeitsgemeinschaft pädiatrischer Stoffwechselstörungen (APS), der Gesellschaft für Neurochirurgie (DGNC) und der Deutschen Gesellschaft für Kinder- und Jugendmedizin (DGKJ) wurden die Strukturvoraussetzungen und die praktischen Aspekte in der Vorbereitung, Durchführung und Nachsorge der Therapie mit Eladocagene exuparvovec erarbeitet. Diskussion Die vorliegende Stellungnahme stellt die notwendigen Rahmenbedingungen für eine qualitätsgesicherte Anwendung von Eladocagene exuparvovec zusammen. Die Behandlung erfordert eine prästationäre, stationäre und poststationäre Betreuung durch ein multiprofessionelles Team in einem spezialisierten und qualifizierten Therapiezentrum. Die Nachsorge der Patienten soll zu einer wissensgenerierenden Versorgung beitragen. Aufgrund von fehlenden Daten zur therapeutischen (Langzeit‑)Wirkung sowie zu Vor- und Nachteilen der verschiedenen stereotaktischen Prozeduren sind ein strukturierter Nachsorgeplan und die Erfassung in einem geeigneten, industrieunabhängigen Register notwendig

Assessment of intellectual impairment, health-related quality of life, and behavioral phenotype in patients with neurotransmitter related disorders: data from the iNTD registry

Inherited disorders of neurotransmitter metabolism are a group of rare diseases, which are caused by impaired synthesis, transport or degradation of neurotransmitters or co-factors and result in various degrees of delayed or impaired psychomotor development. To assess the effect of neurotransmitter deficiencies on intelligence, quality of life, and behavior, the data of 148 patients in the registry of the International Working Group on Neurotransmitter Related Disorders (iNTD) was evaluated using results from standardized age-adjusted tests and questionnaires. Patients with a primary disorder of monoamine metabolism had lower IQ scores (mean IQ 58, range 40-100) within the range of cognitive impairment (<70) compared to patients with a BH4 deficiency (mean IQ 84, range 40-129). Short attention span and distractibility were most frequently mentioned by parents, while patients reported most frequently anxiety and distractibility when asked for behavioral traits. In individuals with succinic semialdehyde dehydrogenase deficiency, self-stimulatory behaviors were commonly reported by parents, whereas in patients with dopamine transporter (DAT) deficiency, DNAJC12 deficiency, and monoamine oxidase A deficiency, self-injurious or mutilating behaviors have commonly been observed. Phobic fears were increased in patients with 6-pyruvoyltetrahydropterin synthase deficiency while individuals with sepiapterin reductase deficiency frequently experienced communication and sleep difficulties. Patients with BH4 deficiencies achieved significantly higher quality of life as compared to other groups. This analysis of the iNTD registry data highlights: a) difference in IQ and subdomains of quality of life between BH4 deficiencies and primary neurotransmitter-related disorders, and b) previously underreported behavioral traits

Genotypic diversity and phenotypic spectrum of infantile liver failure syndrome type 1 due to variants inLARS1

Purpose: Biallelic variants in LARS1, coding for the cytosolic leucyl-tRNA synthetase, cause infantile liver failure syndrome 1 (ILFS1). Since its description in 2012, there has been no systematic analysis of the clinical spectrum and genetic findings. Methods: Individuals with biallelic variants in LARS1 were included through an international, multicenter collaboration including novel and previously published patients. Clinical variables were analyzed and functional studies were performed in patient-derived fibroblasts. Results: Twenty-five individuals from 15 families were ascertained including 12 novel patients with eight previously unreported variants. The most prominent clinical findings are recurrent elevation of liver transaminases up to liver failure and encephalopathic episodes, both triggered by febrile illness. Magnetic resonance image (MRI) changes during an encephalopathic episode can be consistent with metabolic stroke. Furthermore, growth retardation, microcytic anemia, neurodevelopmental delay, muscular hypotonia, and infection-related seizures are prevalent. Aminoacylation activity is significantly decreased in all patient cells studied upon temperature elevation in vitro. Conclusion: ILFS1 is characterized by recurrent elevation of liver transaminases up to liver failure in conjunction with abnormalities of growth, blood, nervous system, and musculature. Encephalopathic episodes with seizures can occur independently from liver crises and may present with metabolic stroke

Assessment of intellectual impairment, health-related quality of life, and behavioral phenotype in patients with neurotransmitter related disorders: Data from the iNTD registry

Inherited disorders of neurotransmitter metabolism are a group of rare diseases, which are caused by impaired synthesis, transport, or degradation of neurotransmitters or cofactors and result in various degrees of delayed or impaired psychomotor development. To assess the effect of neurotransmitter deficiencies on intelligence, quality of life, and behavior, the data of 148 patients in the registry of the International Working Group on Neurotransmitter Related Disorders (iNTD) was evaluated using results from standardized age-adjusted tests and questionnaires. Patients with a primary disorder of monoamine metabolism had lower IQ scores (mean IQ 58, range 40-100) within the range of cognitive impairment (<70) compared to patients with a BH4 deficiency (mean IQ 84, range 40-129). Short attention span and distractibility were most frequently mentioned by parents, while patients reported most frequently anxiety and distractibility when asked for behavioral traits. In individuals with succinic semialdehyde dehydrogenase deficiency, self-stimulatory behaviors were commonly reported by parents, whereas in patients with dopamine transporter deficiency, DNAJC12 deficiency, and monoamine oxidase A deficiency, self-injurious or mutilating behaviors have commonly been observed. Phobic fears were increased in patients with 6-pyruvoyltetrahydropterin synthase deficiency, while individuals with sepiapterin reductase deficiency frequently experienced communication and sleep difficulties. Patients with BH4 deficiencies achieved significantly higher quality of life as compared to other groups. This analysis of the iNTD registry data highlights: (a) difference in IQ and subdomains of quality of life between BH4 deficiencies and primary neurotransmitter-related disorders and (b) previously underreported behavioral traits.Dietmar Hopp Stiftung (DE); Medical Faculty of the University of Heidelberg

Use of an Electrochemical Split Cell Technique to Evaluate the Influence of Shewanella oneidensis Activities on Corrosion of Carbon Steel

Microbially induced corrosion (MIC) is a complex problem that affects various industries. Several techniques have been developed to monitor corrosion and elucidate corrosion mechanisms, including microbiological processes that induce metal deterioration. We used zero resistance ammetry (ZRA) in a split chamber configuration to evaluate the effects of the facultatively anaerobic Fe(III) reducing bacterium Shewanella oneidensis MR-1 on the corrosion of UNS G10180 carbon steel. We show that activities of S. oneidensis inhibit corrosion of steel with which that organism has direct contact. However, when a carbon steel coupon in contact with S. oneidensis was electrically connected to a second coupon that was free of biofilm (in separate chambers of the split chamber assembly), ZRA-based measurements indicated that current moved from the S. oneidensis-containing chamber to the cell-free chamber. This electron transfer enhanced the O2 reduction reaction on the coupon deployed in the cell free chamber, and consequently, enhanced oxidation and corrosion of that electrode. Our results illustrate a novel mechanism for MIC in cases where metal surfaces are heterogeneously covered by biofilms