Disorders in the amino acid metabolism

Amino acids are vital substances without which our metabolism could not assemble proteins. In addition, they have other indispensable tasks, for example, in the nervous system, liver metabolism, growth or build-up of skin, hair and nails. Some amino acids can be produced by the human organism itself, others must necessarily be supplied with food.


The processes involved in the assembly and disassembly of amino acids and proteins in the organism are very complex; a whole range of enzymes and coenzymes are involved. If individuals are defective or are not produced by the body or only in insufficient quantity - which is collectively referred to as enzymopathy - it comes as a result, for example, to a disorder in amino acid metabolism or diseases such as porphyria or Fabry disease.

The faults at a glance

Most often, the defects in amino acid metabolism is that the precursors or intermediates can not be converted to the final amino acid. The result is that these accumulate in the body, the amino acid, however, is lacking or their amount is insufficient to fulfill their function. This leads to damage of tissue and organs by the intermediates and / or deficiency symptoms due to the amino acid deficiency.

In some cases, the transport of amino acids is disturbed, so that they can not be taken up from the urine and transported back into the body, for example.

The amino acid metabolism disorders have one thing in common: They are based on a congenital genetic defect, so they are inherited. Most, however, are very rare. The expression can vary - depending on whether an enzyme is completely absent or only limited in its function.

Diagnosis often difficult

Since a metabolic pathway includes several stations where different enzymes are needed, several disorders can occur. The road to diagnosis is an odyssey in many of the disorders - as most of these diseases are very rare and the symptoms are rather nonspecific, most doctors do not know much about it and the diseases are difficult to detect.

Exceptions are the phenylketonuria and - in Bavaria - the urea cycle defects, since they are already being used in neonates for screening tests and thus are detected early. Often, the therapeutic spectrum is quite limited - in rare diseases, intensive research is hardly worthwhile for pharmaceutical companies.

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