Scientists have crossed a threshold that researchers once considered far beyond reach, successfully using the gene-editing tool CRISPR to target and remove or silence the extra chromosome responsible for Down syndrome in human cells for the very first time. Down syndrome, which affects roughly one in every 700 newborns and is the most common chromosomal condition in the world, has never had a treatment that addresses its actual genetic cause: the presence of a third copy of chromosome 21, which disrupts development in ways that current medicine can only manage symptom by symptom. Two separate research teams have now demonstrated in laboratory settings that CRISPR can go directly to the source of that disruption. A Japanese team from Mie University successfully cut away the extra chromosome entirely and restored more typical cellular behavior, while scientists at Harvard Medical School and Beth Israel Deaconess Medical Center developed a method to silence the chromosome’s activity using a gene that naturally switches off extra chromosomes in the body.
Neither approach is ready for use in living people yet, and both teams are clear that significant safety testing and clinical trials will be required before anything resembling a treatment could exist. But the scientific community has called the combined progress genuinely historic, because for more than half a century since the extra chromosome was identified as the cause of Down syndrome, no credible method to correct it at the genetic level in human cells had ever been found. These experiments represent the first real proof that such a correction is biologically possible, and researchers say the findings also open a new direction for understanding the increased Alzheimer’s disease risk that the condition carries, since chromosome 21 contains the gene most closely linked to Alzheimer’s. Scientists describe it as the beginning of a new chapter for one of the oldest unsolved challenges in human genetics.
Source: https://techfixated.com/scientists-use-crispr-to-remove-the-extra-chromosome-in-down-syndrome-cells/
