DNA Repeat Linked to Higher Alzheimer’s Risk in Chinese Population, Study Shows

It might sound like science‑fiction, but a tiny stretch of DNA could help explain why some people are more prone to Alzheimer’s disease. A team of scientists from Hong Kong, the United States and Europe dug into the genomes of thousands of volunteers and spotted a pattern: the longer the repeat of a CCG sequence in the FAM193B gene, the higher the odds of having Alzheimer’s.

In the Chinese sample – more than 3,000 participants, roughly half of whom had already been diagnosed – individuals with 18 or more CCG repeats were about twice as likely to carry the disease as those with 11 repeats or fewer. The researchers weren’t looking at a single‑letter mutation; they were counting how many times that three‑letter “word” showed up in a row, a kind of genetic spelling error that’s been largely overlooked until now.

When the same analysis was run on the UK Biobank data – over 2,600 Alzheimer’s cases and nearly 23,000 controls of European descent – the link was still there, but far less pronounced. That mirrors what we already know about other Alzheimer’s genes, like APOE, whose impact can shift dramatically depending on ancestry.

Why does this matter? The study showed that more CCG repeats boost the activity of the FAM193B gene. In laboratory neurons, higher FAM193B levels were tied to DNA damage and cell‑death pathways – the same kinds of troublemakers that drive the disease’s hallmark plaques and tangles. Moreover, the FAM193B protein physically interacts with enzymes GSK3α and GSK3β, which, when out of balance, can stir up the toxic beta‑amyloid and tau proteins that underlie Alzheimer’s pathology.

Experts are cautious, though. “We’re still early,” says Harvard neurologist Rudolph Tanzi. The Chinese cohort is relatively small, and the exact role of FAM193B in brain cells is a mystery waiting to be solved. Yet the finding does open a new door for risk prediction. Including this structural variant in genetic screening could sharpen our ability to flag people who might benefit from closer monitoring or preventive strategies, especially in populations where the effect is strongest.

Ultimately, the work underscores a broader point: Alzheimer’s isn’t driven by a single culprit gene. It’s a mosaic of genetic pieces, lifestyle choices and environmental influences. By expanding our view beyond single‑letter changes to include repeat sequences, we get a richer, if more complicated, picture of the disease – and maybe, just maybe, a better chance at staying one step ahead of it.