Deficit of glucose-6-phosphate déshydrogénase

The deficit of glucose-6-phosphate déshydrogénase , or deficit in G6PD , is the enzymatic deficit most widespread in the world. It is often found at the people originating in Africa, of the Indies, of all the Mediterranean basin, the Middle East and the South-east of Asia. It remains underestimated in the populations of the North of Europe and one finds it in the black populations of North America, the Antilles and Brazil. The migrations of populations make that today, it does not act more than one rare deficit, and it is estimated that a minimum from 100.000 to 200.000 overdrawn live in France, without no epidemiological study being still undertaken to confirm it. According to FAO, it would touch 100 million people all over the world. In certain areas, the frequency of the transmitters exceeds 15% of the population.

This disease was called favism because the ingestion of Fève S which contains oxidizing substances, can cause crises of hémolyse acute.

The disease is transmitted genetically on the recessive mode, been dependant on the sexual chromosome X. She is primarily expressed at the subjects of male sex (XY) known as hémizygotes for the deficit, the girls are homozygotes or hétérozygotes, the forms homozygotes being rare. The disease, in the girls homozygotes, with the same translation as among boys.

To have a deficit in G6PD does not mean sick forcing being. Indeed without particular accident, the person is quite bearing and asymptomatic. She will have, during all her life, to know and respect certain instructions to avoid the diseases to which this deficit predisposes.

Thus it will have to never introduce Fève S and never not to be treated with certain drugs (like the anti-paludic for example) and other oxidizing substances. With contrarion, it is established that the deficit in G6PD protects from the Paludisme by supporting the early phagocytosis of parasitized red blood corpuscles.

In the contrary case, it risks an acute haemolytic crisis. Hemoglobin is transformed into methémoglobine and of the bodies of Heinz appear in red blood corpuscles and allow the diagnosis, just like the measurement of remote activity G6PD of the crisis.

The deficit of Glucose-6-phosphate deshydrogénase is thus responsible for haemolytic Anémie congenital of enzymatic origin.

Once the deficit in detected G6PD, the prevention of the accidents is easy.

Physiopathology

The deficit in Glucose-6-phosphate déshydrogénase blocks the initial reaction of oxidation of the Voie of pentoses phosphates. Thus, the under-production of NADPH which results from it, strongly reduces the cellular capacities to fight against the stress oxidant.

The Hématie S use the way of the Pentose S phosphates to create NADPH necessary to the formation of the Glutathion. This last is implied in the reduction in the oxydative stress of the red globule. The Hématie, its cellular Membrane thus weakened, will be destroyed what will cause a Anémie by Hémolyse and a Ictère.

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