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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.
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Objective To explore the excitotoxic role of NMDA receptors in striatal neurons in glutaric aciduria type I (GA1). Methods A GA1 cell model was established by lentivirus-mediated shRNA to GCDH and excessive intake of lysine. The expression levels of NMDA receptors were determined by Western blotting. The striatal neurons were preprocessed by MK801(a NMDA receptor antagonist), then infected with lentivirus and cultured in high concentration lysine. Cell viability was measured using MTT. Apoptosis was assessed using Hoechst33342 staining. Results Compared with the control group, the expression of NR2B protein in the experimental group was increased, and there was statistical difference (P<0.001). The differentces in the cell viability and normal nuclear proportion among experimental group, control group, and MK-801 pretreatment group were statistically significant (P<0.01). The cell viability and normal nucleus proportion in experimental group were significantly lower than those in control group while they were significantly higher in MK-801 pretreated group than those in the experiment group but still significantly lower than those in control group (P all <0.05). Conclusion The accumulation of metabolites in GA 1 played a toxic role in striatal neurons through NMDR receptors.
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Objective To explore the excitotoxic role of NMDA receptors in striatal neurons in glutaric aciduria type I (GA1). Methods A GA1 cell model was established by lentivirus-mediated shRNA to GCDH and excessive intake of lysine. The expression levels of NMDA receptors were determined by Western blotting. The striatal neurons were preprocessed by MK801(a NMDA receptor antagonist), then infected with lentivirus and cultured in high concentration lysine. Cell viability was measured using MTT. Apoptosis was assessed using Hoechst33342 staining. Results Compared with the control group, the expression of NR2B protein in the experimental group was increased, and there was statistical difference (P<0.001). The differentces in the cell viability and normal nuclear proportion among experimental group, control group, and MK-801 pretreatment group were statistically significant (P<0.01). The cell viability and normal nucleus proportion in experimental group were significantly lower than those in control group while they were significantly higher in MK-801 pretreated group than those in the experiment group but still significantly lower than those in control group (P all <0.05). Conclusion The accumulation of metabolites in GA 1 played a toxic role in striatal neurons through NMDR receptors.
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Glutaric aciduria type I (GA I) is an autosomal recessive disorder caused by a deficiency of glutaryl-CoA dehydrogenase. Although over 400 patients confirmed as GA I have been reported, reports from the Asian population had contributed to the minor proportion. We recently diagnosed two cases of GA I confirmed with mutational analysis. Here, we present their rather atypical clinical presentations with genetic characteristics for the first time in Korea. Profound developmental delay from birth, association of hearing loss, and neurological improvement after surgical intervention, were considered to be different clinical features from most reported cases. One patient was a compound heterozygote for p.Ser139Leu and p.Asp220Tyr, and the other for p.Ser139Leu and Glu160X. The mutations of the two alleles (p.Asp220Tyr and p.Glu160X) were novel and reports of p.Ser139Leu were rare both in Western and other Asian populations. These might suggest different genetic spectrum of Korean GA I patients.