Why are children with Down syndrome at a significantly higher risk of developing leukemia?
People with Down syndrome are at greater risk of a wide range of health problems, including heart problems, breathing and hearing difficulties , as well as thyroid problems, but, if that weren’t enough, the risk of developing leukemia in the childhood is 20 times higher than in the general population.
A team of researchers from the Dana-Farber Cancer Institute (USA) has carried out a study to determine the cause of this increased risk, which, according to the study published in the journal Nature Genetics , is nothing more than a palpable genetic connection between the two .
To do this, the scientists used laboratory mice with an extra copy of 31 genes found on chromosome 21 in humans (people with Down syndrome carry three copies of this chromosome instead of two). After testing the B cells (leukemia) in mice, they discovered that these cells were abnormal and grew out of control , just like in patients with acute lymphoblastic leukemia.
After analyzing the B cells of the mice to determine their “molecular signature”, they found that a group of proteins called PRC2 did not work in these abnormal cells , which allowed the B cells to divide and proliferate before they were fully mature. To find out which gene or group of genes were responsible for blocking these proteins, the researchers removed one by one the extra copy of the 31 genes that remained mutated in the mice and saw that, by removing the HMGN1 gene, the cells they stopped growing and died .
“We concluded that the extra copy of the HMGN1 gene is important in turning off the PRC2 protein, which, in turn, increases cell proliferation,” says study co-author Andrew Lane.
