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Propionic acidemia
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop
When propionyl CoA accumulates, other metabolic products are found in the blood and urine. The predominant compound is 3-hydroxypropionic acid; others include tiglic acid, tiglyglycine, butanone, and propionylglycine. In addition, the unusual metabolite methylcitrate is formed by condensation of propionyl CoA and oxaloacetic acid [65]. This compound is an end product of metabolism and is very stable, resistant to conditions of shipment and bacterial contamination. In our hands, it is the most reliable chemical indicator of the presence of this disorder. It is useful in prenatal diagnosis, as well as the initial diagnosis. Odd chain fatty acids may accumulate in body lipids as a consequence of synthesis from propionyl CoA. They may be demonstrated and quantified in erythrocytes [66]. 3-Ureidopropionate is found in the urine [67], a consequence of propionate inhibition of ureidopropionase. The manifestations of patients with inherited deficiency of this enzyme of pyrimidine metabolism are reminiscent of those of propionic acidemic patients with changes in the basal ganglia, and there is in vitro evidence that ureidopropionate is neurotoxic [68]. 2-Methyl-3-oxovaleric acid, a product of self-condensation of two molecules of propionyl CoA, has been a useful metabolite for Lehnert and colleagues [14] for the diagnosis of propionic acidemia. Its reduction yields 3-hydroxy 2-methylvaleric acid. Hyperlysinemia or hyperlysinuria encountered in propionic acidemia [14] appears to reflect study during hyperammonemia, during which lysine accumulates.
Diseases of the Nervous System
Published in George Feuer, Felix A. de la Iglesia, Molecular Biochemistry of Human Disease, 2020
George Feuer, Felix A. de la Iglesia
Congenital dietary lysine intolerance elicits different symptoms from hyperlysinemia. Lethargy, episodes of vomiting, and hepatic coma occur intermittently, associated with increased quantities of ammonia, lysine, and arginine in blood. These symptoms disappear on low protein diet, but can be provoked by the administration of lysine. A partial reduction of hepatic lysine dehydrogenase activity is probably responsible for the metabolic error.
Ocular manifestations in classic homocystinuria
Published in Ophthalmic Genetics, 2021
Patrícia Ioschpe Gus, Karina Carvalho Donis, Diane Marinho, Tiago Franco Martins, Carolina Fischinger Moura de Souza, Rafael Barboza Carloto, Gabriel Leivas, Ida Vanessa Doederlein Schwartz
The prevalence of ectopia lentis in patients with HCU is around 70% until age 7, rising to 95% by the fifth decade and is classically inferior or inferonasal (13,14,15). In this series, however, 57% of the patients had a superior dislocation – usually described in Marfan patients. Since the lens may dislocate to any direction, its position in a given patient cannot be considered pathognomonic of HCU nor Marfan, because other heritable disorders may be associated with ectopia lentis: Ehlers–Danlos syndromes, Weill–Marchesani syndrome, hyperlysinemia, sulfite oxidase deficiency and Treacher Collins syndrome (16). It is always suspicious of a genetic disease, indeed, in the absence of eye trauma history.