First detected in the 1950s in Africa, the Zika virus has the same vector as dengue and chikungunya: the Aedes Aegypti mosquito; its hosts include monkeys as well as humans.
Zika virus fever is life-threatening and since 2007 there have been a number of dangerous outbreaks in humans, especially in South America and Oceania. When the carrier mosquito bites a person, the virus infects their dendritic cells and then spreads to the lymph nodes and blood.
In pregnant women, it constitutes an important risk in the development of microcephaly by the fetus in the first three months of gestation.
However, according to research, there could be a genetic component involved in the susceptibility to contract the Zika virus.
About 6% to 12% of babies born to mothers infected with the Zika virus during pregnancy will have congenital Zika syndrome (CZS). Therefore, if not all babies are affected by the syndrome, what is the variable that allows it?
The study analyzed three pairs of Brazilian twin babies, revealing genetic clues about how the Zika virus contracts and affects the human body when the virus is congenital, that is, it is transmitted from the mother to the fetus.
According to the results, neuronal cells unaffected by the syndrome showed different rates of virus infection, and different RNA expressions in genes associated with neuronal development. Expression imbalance occurs even before Zika virus infection in vitro.
This means that there must be a genetic or epigenetic influence on the susceptibility to suffering from CZS and microcephaly.
In turn, the researchers also concluded that a single gene cannot explain the cases of development of CSZ or brain resistance to the Zika virus.
The researchers, led by Dr. Mayana Zatz and Maria Rita Passos-Bueno, geneticists at the Human Genome and Stem Cell Research Center of the University of São Paulo (USP), published their findings in the journal Nature Communications .
Twins, key in the study of genetic diseases
Twins provide unique information to answer whether a certain condition has an environmental or rather genetic cause. “If genetic factors are determining factors for a congenital disease, there should be more concordance between identical (monozygotic) twin babies than between dizygotic or non-identical twins,” the researchers note.
“Identical siblings should be more often affected than dizygotic twins, who are probably ‘discordant,’ that is, one affected and one unaffected.”
” If the baby has these genetic susceptibility factors, we believe that they will not have microcephaly unless they are infected with the Zika virus. Perhaps we can identify these people and prioritize them in a future vaccine strategy,” according to Dr. Mayana Zatz .
