They have managed to eliminate the additional chromosome that causes Down syndrome in the laboratory cells

2025/03/03 Etxebeste Aduriz, Egoitz - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Genetika
• Medikuntza

Some Japanese researchers have succeeded in removing the additional copy of chromosome 21 that causes Down syndrome in human laboratory cells. Although it is far from being used clinically, this experiment opens up a new opportunity to treat this syndrome. The study was published in the journal PNAS Nexus.

Down syndrome affects one in every 700 births. It is caused by the trisomy of chromosome 21, which means having three copies instead of two copies of the chromosome. Usually, the descendant receives from each chromosome a copy of the mother and another of the father. In the case of Down syndrome, however, two copies of chromosome 21 from one of the parents are passed on to the offspring.

The two copies of each chromosome are not identical. They usually have the same genes, but they have multiple genetic variants that can alter the functioning of all these genes. Well, Japanese researchers have taken advantage of this difference to identify the specific sequences of one of the 21 duplicated chromosomes and, using the CRISPR-Cas9 technique, to undo them by cutting them into multiple fragments.

Thus, they have used this technique with induced pluripotent stem cells derived from skin cells of a patient with Down's syndrome; and they have obtained that these cells contain only two copies of chromosome 21, one inherited from the father and the other from the mother. They observed an improvement in cell viability and cell stress in this way, and as a result, they believe that the method has the potential to reverse the adverse effects of trisomy.

Researchers have made it clear that the technique is still at a very early stage. They stress that there are some problems that need to be solved and that it is not yet ready for use in vivo in animals and even less in people. They point out that some of the challenges include improving chromosome clearance rates and developing methods that do not require DNA cutting to minimize the risk of unintentional genome changes.