Clinical and Nutritional Evolution of 24 Patients with Glutaric Aciduria Type 1 in Follow-up at a Center Specialized in Inborn Errors of Metabolism in Chile

Abstract Introduction: Glutaric Aciduria Type 1 (GA-1) is produced by the enzymatic deficiency of glutaryl-CoA-dehydrogenase (GCDH), leading to the accumulation of glutaric acid (GA). 90% of patients without early treatment present acute encephalopathic crisis (AEC), followed by disabling neurological symptoms. The treatment consists of a low lysine (Lys) diet, protein substitute lys-free, tryptophan-reduced (PS) and L-carnitine. Objectives: Describe the clinical and nutritional evolution of a cohort of GA-1 patients at a national referral center in Chile. Methodology: Retrospective study of 24 patients diagnosed with GA-1 between 1998-2020 and referred to the Institute of Nutrition and Food Technology (INTA) of University of Chile. Results: Age at diagnosis was 19±27 months; 10/24 presented AEC and neurological sequelae. The cases without AEC (14/24) 8 presented neurological compromise: psychomotor development delay, abnormal movements and pyramidal syndrome. Nutritional evaluation: 12/24 were malnourished by deficiency, <6 years old group (12/24): 11 cases were found to have Lys and PS, ≥6 years old (12/24): 9/12 did not receive PS. All had normal free carnitine levels. Conclusion: GA-1 has variable symptoms with neurological involvement AEC or insidious start. Is essential to maintain a long-term follow-up and consider its inclusion in neonatal screening programs.

Elevated levels of BDNF and cathepsin-d as possible peripheral markers of neurodegeneration in plasma of patients with glutaric acidemia type I.

Glutaric acidemia type I (GA1) is caused by severe deficiency of glutaryl-CoA dehydrogenase activity, resulting in an accumulation of glutaric acid and glutarylcarnitine (C5DC) in the organism. Patients affected by GA1 are asymptomatic in the neonate period but usually manifest chronically progressive neurodegeneration apart from severe encephalopathic crises associated with acute striatum necrosis. Neurological manifestations like dyskinesia, dystonia, hypotonia, muscle stiffness, and spasticity are present. Treatment is based on protein/lysine restriction and l-carnitine supplementation. In this work, we evaluated markers of neurodegeneration and inflammation, namely BDNF (brain-derived neurotrophic factor), NCAM (neuronal adhesion molecule), PDGF-AA (platelet-derived growth factor), and cathepsin-d in plasma of six treated GA1 patients. We first found marked increases of plasma C5DC concentrations in GA1 patients, as well as increased levels of the markers BDNF and cathepsin-d as compared to those of age-matched healthy children. Furthermore, C5DC concentrations were highly correlated with the levels of cathepsin-d. These results may demonstrate that brain tissue degeneration is present in GA1 patients and that there is a relationship between increased metabolites concentrations with this process. To the best of our knowledge, this is so far the first study showing altered peripheral parameters of neurodegeneration and inflammation in GA1 patients.

Oxidative damage in glutaric aciduria type I patients and the protective effects of l-carnitine treatment.

The deficiency of the enzyme glutaryl-CoA dehydrogenase, known as glutaric acidemia type I (GA-I), leads to the accumulation of glutaric acid (GA) and glutarilcarnitine (C5DC) in the tissues and body fluids, unleashing important neurotoxic effects. l-carnitine (l-car) is recommended for the treatment of GA-I, aiming to induce the excretion of toxic metabolites. l-car has also demonstrated an important role as antioxidant and anti-inflammatory in some neurometabolic diseases. This study evaluated GA-I patients at diagnosis moment and treated the oxidative damage to lipids, proteins, and the inflammatory profile, as well as in vivo and in vitro DNA damage, reactive nitrogen species (RNS), and antioxidant capacity, verifying if the actual treatment with l-car (100 mg kg-1 day-1 ) is able to protect the organism against these processes. Significant increases of GA and C5DC were observed in GA-I patients. A deficiency of carnitine in patients before the supplementation was found. GA-I patients presented significantly increased levels of isoprostanes, di-tyrosine, urinary oxidized guanine species, and the RNS, as well as a reduced antioxidant capacity. The l-car supplementation induced beneficial effects reducing these biomarkers levels and increasing the antioxidant capacity. GA, in three different concentrations, significantly induced DNA damage in vitro, and the l-car was able to prevent this damage. Significant increases of pro-inflammatory cytokines IL-6, IL-8, GM-CSF, and TNF-α were shown in patients. Thus, the beneficial effects of l-car presented in the treatment of GA-I are due not only by increasing the excretion of accumulated toxic metabolites, but also by preventing oxidative damage.

Novel contiguous gene deletion in peruvian girl with Trichothiodystrophy type 4 and glutaric aciduria type 3.

Trichothiodystrophy type 4 is a rare autosomal recessive and ectodermal disorder, characterized by dry, brittle, sparse and sulfur-deficient hair and other features like intellectual disability, ichthyotic skin and short stature, caused by a homozygous mutation in MPLKIP gene. Glutaric aciduria type 3 is caused by a homozygous mutation in SUGCT gene with no distinctive phenotype. Both genes are localized on chromosome 7 (7p14). We report an 8-year-old female with short stature, microcephaly, development delay, intellectual disability and hair characterized for dark, short, coarse, sparse and brittle associated to classical trichorrhexis microscopy pattern. Chromosome microarray analysis showed a 125 kb homozygous pathogenic deletion, which includes genes MPLKIP and SUGCT, not described before. This is the first case described in Peru of a novel contiguous gene deletion of Trichothiodystrophy type 4 and Glutaric aciduria type 3 performed by chromosome microarray analysis, highlighting the contribution and importance of molecular technologies on diagnosis of rare genetic conditions.

Higher Vulnerability of Menadione-Exposed Cortical Astrocytes of Glutaryl-CoA Dehydrogenase Deficient Mice to Oxidative Stress, Mitochondrial Dysfunction, and Cell Death: Implications for the Neurodegeneration in Glutaric Aciduria Type I.

Patients affected by glutaric aciduria type I (GA-I) show progressive cortical leukoencephalopathy whose pathogenesis is poorly known. In the present work, we exposed cortical astrocytes of wild-type (Gcdh +/+ ) and glutaryl-CoA dehydrogenase knockout (Gcdh -/- ) mice to the oxidative stress inducer menadione and measured mitochondrial bioenergetics, redox homeostasis, and cell viability. Mitochondrial function (MTT and JC1-mitochondrial membrane potential assays), redox homeostasis (DCFH oxidation, nitrate and nitrite production, GSH concentrations and activities of the antioxidant enzymes SOD and GPx), and cell death (propidium iodide incorporation) were evaluated in primary cortical astrocyte cultures of Gcdh +/+ and Gcdh -/- mice unstimulated and stimulated by menadione. We also measured the pro-inflammatory response (TNFα levels, IL1-ß and NF-ƙB) in unstimulated astrocytes obtained from these mice. Gcdh -/- mice astrocytes were more vulnerable to menadione-induced oxidative stress (decreased GSH concentrations and altered activities of the antioxidant enzymes), mitochondrial dysfunction (decrease of MTT reduction and JC1 values), and cell death as compared with Gcdh +/+ astrocytes. A higher inflammatory response (TNFα, IL1-ß and NF-ƙB) was also observed in Gcdh -/- mice astrocytes. These data indicate a higher susceptibility of Gcdh -/- cortical astrocytes to oxidative stress and mitochondrial dysfunction, probably leading to cell death. It is presumed that these pathomechanisms may contribute to the cortical leukodystrophy observed in GA-I patients.

Experimental evidence that overexpression of NR2B glutamate receptor subunit is associated with brain vacuolation in adult glutaryl-CoA dehydrogenase deficient mice: A potential role for glutamatergic-induced excitotoxicity in GA I neuropathology.

Glutaric aciduria type I (GA I) is biochemically characterized by accumulation of glutaric and 3-hydroxyglutaric acids in body fluids and tissues, particularly in the brain. Affected patients show progressive cortical leukoencephalopathy and chronic degeneration of the basal ganglia whose pathogenesis is still unclear. In the present work we investigated parameters of bioenergetics and redox homeostasis in various cerebral structures (cerebral cortex, striatum and hippocampus) and heart of adult wild type (Gcdh(+/+)) and glutaryl-CoA dehydrogenase deficient knockout (Gcdh(-/-)) mice fed a baseline chow. Oxidative stress parameters were also measured after acute lysine overload. Finally, mRNA expression of NMDA subunits and GLT1 transporter was determined in cerebral cortex and striatum of these animals fed a baseline or high lysine (4.7%) chow. No significant alterations of bioenergetics or redox status were observed in these mice. In contrast, mRNA expression of the NR2B glutamate receptor subunit and of the GLT1 glutamate transporter was higher in cerebral cortex of Gcdh(-/-) mice. Furthermore, NR2B expression was markedly elevated in striatum of Gcdh(-/-) animals receiving chronic Lys overload. These data indicate higher susceptibility of Gcdh(-/-) mice to excitotoxic damage, implying that this pathomechanism may contribute to the cortical and striatum alterations observed in GA I patients.

Aciduria glutárica tipo I / Glutaric aciduria, type I

La aciduria glutárica tipo I se produce por deficiencia de la enzima glutaril-CoA deshidrogenasa involucrada en el catabolismo de la L-lisina, L-hidroxilisina y L-triptófano lo que ocasiona acumulación de los ácidos glutárico y 3 hidroxiglutárico responsables del compromiso neurológico severo característico de esta enfermedad. La sospecha y diagnóstico de las enfermedades metabólicas constituyen un reto para el personal de salud dada su baja incidencia. En el caso de la aciduria glutárica tipo I se trata de una enfermedad para la cual se poseen los recursos técnicos para el diagnóstico y tratamiento nutricional, su instauración previa a la aparición de encefalopatía aguda, que ocasionan daños irreversibles en el sistema nervioso central, mejora el pronóstico y disminuye el grado de discapacidad. En esta publicación se reportan 5 casos con diagnóstico clínico y bioquímico de aciduria glutárica tipo I que ilustran el espectro clínico y el proceso diagnóstico y de tratamiento en el medio colombiano. Los pacientes se encuentran en seguimiento por los servicios de Neuropediatría.

Glutaric aciduria type i is a disorder resulting trom the deficiency ot the glutaryl-CoA dehydrogenase, enzyme involved in the catabolism ot L-lysine, L-hydroxy-lysine y L-tryptophan causing the accumulation ot its derivatives glutaric acid and 3-hydroxy-glutaric acid which are responsible tor the severe neurological involvement observed in this disease. The diagnosis ot metabolic disorders represents a challenge tor health-care services given its low incidence. Glutaric aciduria type I is a disease tor which there are available technical resources tor diagnosis as well as the nutritional therapy that when set prior to acute encephalopathy, who results in irreversible damage ot central nervous system, can improve the prognosis and decrease the disability ot patients. This publication report 5 cases with clinical and biochemical diagnosis ot glutaric aciduria type i that show the clinical spectrum the diagnostic and treatment approach ot this pathology in Colombia. All the patients are being followed by neuropediatrics services.

Estudio de pacientes con aciduria glutarica tipo II, mediante la incubacion de fibroblastos con acidos palmitico y miristico tritiados / Study of patients with type II glutaric aciduria by incubation of fibroblasts with tritiated palmitic and myristic acids

Introduccion: la aciduria glutarica tipo II, o deficiencia multiple de acil-CoA deshidrogenasas,es un trastorno causado por deficiencia de la flavoproteina de transferencia de electrones,de su oxidorreductasa o de ambas; se trata de una enfermedad metabolica autosomica recesiva, caracterizada por acidosis, hipoglicemia, aciduria organica, olor a pies sudados y malformaciones en cerebro y riñones. Objetivo: analizar las tasas de oxidacion de sustratos tritiados por fibroblastos de pacientescon aciduria glutarica tipo II. Materiales y metodos: se incubaron fibroblastos de dos pacientes con aciduria glutarica tipoII y de 20 controles en presencia de acidos palmitico y miristico tritiados. Resultados: se encontro muy deprimida (16%-18%) la oxidacion de los sustratos tritiados porlos fibroblastos procedentes de pacientes con aciduria glutarica tipo II en comparacion con los controles. Conclusion: la prueba estudiada permite la confirmacion in vitro del diagnostico de aciduriaglutarica tipo II.

Introduction: Glutaric aciduria type II (GA II), or multiple acyl-CoA dehydrogenase deficiency, is a disorder caused by deficiency of either electron transport flavoprotein or electron transport flavoprotein oxyreductase. It is an autsomal recessive metabolic disease, characterized by acidosis, hypoglycemia, organic aciduria, sweat-sock odour, and malformations in brain and kidneys. Objective: To analyse the oxidation rate of tritiated substrates by fibroblasts of patients with GA II. Materials and methods: Fibroblasts of two patients with GA II were incubated with tritiated palmitic and myristic acids. Results: Oxidation of tritiated substrates by fibroblasts of patients with GA II was very depressed (16%-18%) in comparison with controls. Conclusion: Diagnosis of GA II may be confirmed in vitro by the studied test.