Aminoaciduria
Other namesUrine amino acids [1]
Share of amino acid in various human diets and the resulting mix of amino acids in human blood serum. Glutamate and glutamine are the most frequent in food at over 10%, while alanine, glutamine, and glycine are the most common in blood.
ComplicationsSevere protein loss in the blood
Risk factorsLiver disease, malnutrition, kidney disease

Aminoaciduria occurs when the urine contains abnormally high amounts of amino acids.[2] In the healthy kidney, the glomeruli filter all amino acids out of the blood, and the renal tubules then reabsorb over 95% of the filtered amino acids back into the blood.[3]

In overflow aminoaciduria, abnormally high concentrations of amino acids in the blood plasma overwhelm the resorptive capacity of the renal tubules, resulting in high concentrations of amino acids in the urine.It is estimated that about 20 to 25% of the inmates of lunatic asylums are suffering from one of the aminoacidurias[4] This may be caused by congenital disorders of amino acid metabolism,[3] for example, phenylketonuria,[5] or may be secondary to liver disease.[3]

In renal aminoaciduria, the renal tubules are unable to reabsorb the filtered amino acids back into the blood, causing high concentrations of amino acids in the urine.[5] This may be caused by a defect in the transport proteins in the renal tubule, for example, as occurs in Hartnup disease,[5] or may be due to damage to the kidney tubule, for example, as occurs in Fanconi syndrome.[4]

References

  1. ^ "Aminoaciduria". Medline. NIH. Retrieved 18 March 2019.
  2. ^ "Aminoaciduria". Mosby's Medical Dictionary (9th ed.). Mosby. 2013. p. 79. ISBN 9780323112581.
  3. ^ a b c Schück, O (1984). "Amino acids excretion. Physiology and pathophysiology". Examination of Kidney Function. Translated by Cort, JH. Dordrecht: Springer Netherlands. p. 252. ISBN 9789400956605.
  4. ^ a b Crook, Martin Andrew (2012). "Chapter 27: Inborn errors of metabolism". Clinical biochemistry and metabolic medicine (8th ed.). London: Hodder Arnold. pp. 371–383. ISBN 9781444144154.
  5. ^ a b c Mundt, LA; Shanahan, K (2011). "Chapter 7: Urinary and metabolic diseases and related urinalysis findings. Aminoacidurias". Graff's textbook of routine urinalysis and body fluids (2nd ed.). Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins Health. pp. 203–210. ISBN 9781582558752.

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Classification
Components and results of urine tests
Inborn error of amino acid metabolism
Categories