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No, although the cases are less known. “The distribution of Down syndrome is the same for everyone”, says geneticist Paulo Alberto Otto, from the University of São Paulo (USP). The syndrome may not distinguish color before birth, but there is a possibility that it will some years later. A 2001 study by the US Centers for Disease Control and Prevention concluded that, on average, whites with the syndrome live twice as long as blacks. However, the American agency itself emphasizes that this statistical data refers to a single study and, as specialists still do not know how to explain the reason for such disparity, the subject still deserves further research.
What is certain, however, is that Down syndrome is more common than people think: out of every 800 children, one is born with the problem. The cause of the syndrome is an extra chromosome embedded in the DNA, the material that carries our genetic information. Normally, people have their genes distributed on 46 chromosomes, which come in 23 pairs. Those with Down syndrome have an extra chromosome on pair number 21, making a total of 47. This DNA disorder is what causes the familiar symptoms, such as a flat face, flabby muscles, heart problems and mental retardation, which can be mild or acute.
Mothers cannot completely prevent Down syndrome, but there is a factor that greatly influences the possibility of having a child with the syndrome: maternal age. In women under 35, the incidence is one child with the problem for every thousand births. For mothers over 40, the ratio reaches one case for every 100 births.