For people carrying a mutation that causes the rare genetic disease 鈥� pyruvate kinase deficiency 鈥� it鈥檚 not all bad news. The mutation also protects against malaria.
About one in 20,000 people have two copies of a genetic mutation that prevents red blood cells from producing energy and causes anaemia. Patients with the condition often die young.
But people with one mutated pyruvate kinase (PK) gene might be spared from the malaria parasite Plasmodium falciparum, says , a geneticist at McGill University in Montreal who led the new study. 鈥淭hese guys are absolutely normal; they don鈥檛 know that they have one copy of the mutation,鈥� he says.
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Offering resistance
Gros鈥� team is now collecting blood samples in areas rife with malaria to determine whether the mutation offers some resistance in people with one mutation. 鈥淚n one or two years max we鈥檒l have the answer,鈥� he says.
About 300 million people contract malaria each year, and one million die.
Another disease, sickle cell anaemia, protects against malaria in a similar way. Patients with a single mutation in a gene for the blood protein haemoglobin have partial resistance to malaria, while two copies spell disease.
Easy targets
Gros and colleagues tracked down several patients and collected blood from them. When the researchers tried infecting the red blood cells with P. falciparum, the sickly cells were virtually impervious to the parasite.
Some parasites managed to invade, but those cells proved easier targets for the immune system. White blood cells destroyed the infected cells in a Petri dish.
Gros鈥� team performed the same tests in cells of people who had only one mutation in the PK gene. Their red blood cells easily succumbed to the malaria parasite. However, white blood cells made easy work of the infected cells. This suggests that people with PK mutations 鈥� but no disease 鈥� might get some protection from malaria, Gros says.
That condition would be hard to mimic with a drug, says , an infectious disease expert at Brigham and Women鈥檚 Hospital in Boston, Massachusetts. A drug that blocks PK could kill off red blood cells. 鈥淚t is not change that we would want to create through drugs,鈥� she says.
Journal reference: (DOI: 10.1056/NEJMoa072464)
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