Silence the bad copy, spare the good one: a designer drug strand cuts a toxic brain protein by 90%

Spinocerebellar ataxia type 3 — also called Machado-Joseph disease — is a rare inherited illness that gradually takes away a person's balance, walking, speech and eye control. It comes from one faulty copy of a gene: people carry two copies, and while one makes a harmful version of a protein called ataxin-3, the other makes the healthy version the body still needs. That is why earlier drug attempts struggled — they knocked down both copies at once. A team at the German Center for Neurodegenerative Diseases (DZNE) and the Hertie Institute at the University of Tübingen, with colleagues in Bonn, London and Portugal, studied the genes of 79 people with the disease and found tiny spelling differences between the two copies. They then built short, drug-like strands designed to spot those differences and destroy only the faulty copy's messages. In human brain cells grown in a dish, the best strand cut the toxic protein by about 90% while leaving the healthy protein largely untouched. The work, published in Science Translational Medicine, is still at the laboratory stage — human trials are some way off — but it is a clear first blueprint for treating this disease at its root.

SDG 3 · Good health and well-being — Mechanism: tech innovation