Organic acidaemias

Key Information

Appropriate Tests


A possible genetic basis should be considered in children with metabolic acidosis not attributable to another disorder, especially if the acidosis cannot be explained by elevated lactate and/or ß-hydroxybutyrate.

Blood gas arterial or venous.

Organic acids urine (collected during acidotic episode); a normal result, when not acutely ill, does not exclude these disorders. In some diseases (eg, biotinidase deficiency) metabolic acidosis may not occur, but the abnormal organic acids can be detected in the urine.

Identification of the specific disorder depends on the pattern of organic acids excreted during attacks.

Ammonia and Glucose should be measured, as many organic acidaemias are associated with hyperammonaemia and/or hypoglycaemia.

See also Hyperammonaemia, Hypoglycaemia

Naming of specific disorders is usually based on the acid(s) excreted or the deficient enzyme(s).

Specific disorders


Genetic lactic acidosis

L-Lactate, Pyruvate may assist in determining the cause of Lactic acidosis.

Genetic ketoacidosis

ß - Hydroxybutyrate.

Methylmalonic acidaemia

Homocysteine (some types also have Homocystinuria).

Medium chain acyl CoA dehydrogenase deficiency

Molecular genetics.

Maple syrup urine disease

Amino acids urine (leucine, isoleucine, valine).

Acute manifestations


Unexplained metabolic acidosis

See Acidosis - metabolic





Unusual body odour


Chronic manifestations


Psychomotor regression


Failure to thrive




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