Pyridoxine deficiency

Pyridoxine (also known as B6 deficiency ) is a Kinderkrankeit, which is caused by lack of pyridoxine (vitamin B6). In infants with pyridoxine deficiency can be seen this mostly in the first 12 months of life, because pyridoxine is a coenzyme responsible for many important metabolic reactions in humans. This disease is rarely observed even in the developing countries.

Symptoms

The disease shows itself in several important symptoms such as cramps, irritability, cheilitis (inflammation of the lips ), conjunctivitis and neurological symptoms. In patients who received isoniazid, pyridoxine deficiency can lead to sideroblastic anemia because pyridoxine is an important cofactor in the synthesis of heme.

Rare forms

In family pyridoxinabhängigen epilepsy seizures convulsions occur at birth or shortly thereafter. It has been speculated that the cause of seizures in pyridoxine deficiency lies in abnormalities in the normal ratio of glutamic acid to GABA. Relationships with the ALDH7A1 gene have been identified. Irritability and other neurological symptoms such as confusion, here are common. Anemia have also been documented as a symptom.

Causes

The main cause is lack of pyridoxine in the diet. Another cause of vitamin B6 deficiency is the use of the tuberculosis drug isoniazid. In this case, vitamin B6 is prescribed substitutively usually.

Pathophysiology

Pathophysiologically both the decarboxylation of glutamic acid to γ -aminobutyric acid (GABA, a neurotransmitter ) and the transamination of glutamic acid to α -ketoglutaric acid in animals are reduced with pyridoxine. Neurological symptoms can be best solved by a reduced affinity of pyridoxine to apoenzyme, which in turn can only be achieved by increasing the tissue levels of the enzyme.

Frequency

There were a few cases in the years 1952-1953, especially in the United States in children who have received a breast milk substitute without pyridoxine. A test of pyridoxine can be carried out by measuring the value of the erythrocyte - aspartate aminotransferase and transketolase in the serum.

Therapy

For a treatment of the missing vitamin pyridoxine is replaced. Penicillamine or hydrazides, isoniazid are, because of their unwanted side effect of provoking deficiency symptoms, rarely used.