A Development in Gene Editing That Could Lead to a Treatment for Down Syndrome

SadaNews - Researchers have developed a modified version of the gene editing tool known as CRISPR, with early experiments suggesting it may be able to "neutralize" the extra chromosome that causes Down syndrome.

Individuals with Down syndrome are born with an extra copy of chromosome 21, resulting in a total of 47 chromosomes instead of the normal 46.

Dr. Volny Shin, who led the study at Beth Israel Deaconess Medical Center in Boston, said, "Because of this extra copy, several genes become disrupted, contributing to cognitive disabilities and early-onset Alzheimer's disease associated with this condition."

Shin added that due to the unclear issue of which of the hundreds of genes on the extra chromosome is responsible for these effects, neutralizing the entire chromosome would be the optimal treatment. In biologically normal females, a gene called XIST silences or neutralizes the extra X chromosome present in all female cells except for egg cells.

Researchers previously speculated that introducing XIST into the extra chromosome 21 would similarly neutralize its function, but technical constraints often hindered their attempts to insert the gene. Shin noted that one of the challenges they faced was that XIST must be introduced into only one of the three copies of chromosome 21 in the cell, and that this must happen in as many cells as possible. According to a report published in the Proceedings of the National Academy of Sciences, the modified CRISPR version developed by the team enhanced the integration of the XIST gene into the extra chromosome by about 30 times compared to the conventional CRISPR approach.

Although this technique is still in the laboratory testing stage, researchers hope it will lead to treatments in the future. Dr. Ryotaro Hashizumi from Mie University Hospital in Japan, who did not participate in the research, stated that although the strategy to neutralize the chromosome is "very promising" for Down syndrome, and enhancing the efficiency of XIST gene insertion is "very important overall," the new results only represent proof of concept at the cellular level.