17/07/2025
Japanese scientists at Mie University, led by Dr. Ryotaro Hashizume, have achieved a groundbreaking feat by using CRISPR to remove the extra chromosome 21 that causes Down syndrome, restoring normal cell function.
Affecting 1 in 700 births worldwide, Down syndrome results from an extra copy of chromosome 21, leading to intellectual disabilities, distinctive features, and health issues like heart defects and early-onset Alzheimer’s.
The team’s precision gene-editing technique, “allele-specific editing,” trains CRISPR-Cas9 to target unique sequences on the extra chromosome, cutting it to destabilize and naturally discard it during cell division, leaving the normal pair intact.
The study, detailed in Nature Biotechnology, achieved up to 30.6% success in removing the extra chromosome, with treated cells—both stem cells and mature skin cells from Down syndrome patients—showing normalized gene expression, protein production, and survival rates.
This marks the first time the root cause has been addressed at the cellular level, offering unprecedented hope. The establishment lauds it as a potential game-changer for preventing complications that shorten lives, with average life expectancy around 60 years.
However, skepticism remains: the 30.6% efficiency, while promising, is far from universal, and off-target edits or mosaicism risks—where some cells retain the extra chromosome—need scrutiny.
Clinical applications are years away, requiring extensive safety trials, and ethical concerns about germline editing linger.
