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Role of Tandem Mass Spectrometry in Diagnosis and Management of Inborn Errors of Metabolism
Published in P. Mereena Luke, K. R. Dhanya, Didier Rouxel, Nandakumar Kalarikkal, Sabu Thomas, Advanced Studies in Experimental and Clinical Medicine, 2021
Kannan Vaidyanathan, Sandhya Gopalakrishnan
There are some disorders which are not very dangerous to the child, (Essential pentosuria, alkaptonuria, etc.). Some of these, like alkaptonuria, scare the parents because of the symptoms, blackish discoloration of diapers, but other than skeletal abnormalities which appear in the 4th–5th decade of life, they do not produce harm even in adult life. There is accumulation of alkaptone bodies in the patients’ bones which like to blackish discoloration of vertebrae and other bones in this condition. However, the vast majority of metabolic disorders are dangerous and to publicize them as benign and easily treatable is a dangerous tendency which should be resisted. Most of the metabolic disorders can be treated, with special diets or avoidance of particular food stuff and other specific measures. However, treatment has to be started very early in life, and has to be continued for a very long time, and in most cases for a lifetime.
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Published in Anton Sebastian, A Dictionary of the History of Medicine, 2018
Pentosuria [Greek: pente, five + oureon, urine] Condition described by Ernst Leopold Salkowski (1844–1923) of Berlin in 1895. Further work was done by H. Aron in 1913. The Bial test for pentose sugars in urine, using hydrochloric acid as one of the reagents, was devised by German physician, Manfred Bial (1870–1908).
Carbohydrate metabolism
Published in Martin Andrew Crook, Clinical Biochemistry & Metabolic Medicine, 2013
Non-glucose-reducing substances are identified by chromatography and specific tests. The significance of a Clinitest-positive result varies with the substances, which are as follows. Glucose.Glucuronates are relatively common urinary reducing substances. Numerous drugs, such as salicylates and their metabolites, are excreted in the urine after conjugation with glucuronate in the liver.Galactose is found in the urine in galactosaemia.Fructose may appear in the urine after very large oral doses of sucrose, or after excessive fruit ingestion, but usually fructosuria is due to one of two rare inborn errors of metabolism, both transmitted as autosomal recessive disorders: – essential fructosuria is usually a benign condition (hepatic fructokinase deficiency),– hereditary fructose intolerance is characterized by hypoglycaemia that may lead to death in infancy.Lactose. Lactosuria may occur in: – late pregnancy and during lactation,– lactase deficiency.Pentoses. Pentosuria is very rare. It may occur in: – alimentary pentosuria, after excessive ingestion of fruits such as cherries and grapes – the pentoses are arabinose and xylose,– essential pentosuria, a rare recessive disorder due to L-xylulose reductase deficiency, characterized by the excretion of xylose – it is usually benign.Homogentisic acid appears in the urine in the rare inborn error alkaptonuria. It is usually recognizable because it forms a blackish precipitate in urine on standing. Urea and creatinine may give weak positive results at high concentrations.
Pharmacogenetics and drug metabolism: historical perspective and appraisal
Published in Xenobiotica, 2020
Robert L. Smith, Stephen C. Mitchell
The work of Archibald Edward Garrod (1857–1936) helped to fuse a liason between the emerging sciences of genetics, chemical pathology and biochemistry (physiological chemistry). His interest in alkaptonuria, helped cement the understanding that inefficiencies in enzyme pathways could lead to clinical conditions. This seminal work rested upon the ability to see a darkening of the urine caused by the oxidation of homogentisic acid (melanic acid), an intermediate in the breakdown of tyrosine and phenylalanine that accumulates owing to underactivity of homogentisic dioxygenase (Garrod, 1902). This outward clinical sign of darkening urine had been observed centuries ago (Scribonius, 1584) as mentioned by Garrod himself. His findings on alkaptonuria together with albinism, cystinuria and pentosuria (sometimes known as Garrod’s tetrad) were given in a series of four lectures, the Croonian lectures, in 1908 (Garrod, 1908) later published in book form (Garrod, 1909) (Figure 1). The revised second edition of his book included the other hereditary ailments of congenital steatorrhea and congenital porphyrinuria (Garrod, 1923).