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FAM193B DNA repeat is linked to Alzheimer’s disease across two populations

A repeated stretch of DNA in FAM193B is associated with Alzheimer’s disease in Chinese and UK samples. The peer-reviewed study combines sequencing with cell experiments to examine how the repeat affects gene activity. The association is weaker in the UK comparison, and the work offers a biological research lead rather than a clinically validated test of an individual’s risk.

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An anatomical brain teaching model beside unequal repeat strips and two comparison groups on a laboratory table.

FAM193B repeat lengths differ between cases and controls

A repeated DNA sequence in the regulatory region of FAM193B, a gene whose activity the study examined, was associated with Alzheimer’s disease. The peer-reviewed investigation combined long-read and short-read sequencing with experimental work on cells. Structural variations, including insertions and repeat lengths, added genetic information beyond changes in individual DNA letters.[1], [2]

The Chinese analysis included 1,516 people with Alzheimer’s disease and 1,674 controls. Repeats of at least 18 units appeared in 30.9 per cent of cases and 19.9 per cent of controls. The odds ratio was 2.11, with a confidence interval of 1.68–2.65; this comparison gives no individual’s absolute lifetime probability of illness.[1]

The UK association is weaker at its tested threshold

The UK Biobank comparison used 2,674 cases and 22,996 controls. At a threshold of at least 19 repeats, the odds ratio was 1.21 with a confidence interval of 1.05–1.41. The association’s size therefore differed between these populations. A combined structural-variant and single-letter model distinguished study groups better than either component alone, without clinical validation as a screening test.[1]

Cell experiments connect longer repeats to gene activity

Cell experiments compared constructs containing 25 and 11 repeats. The longer repeat increased binding by MAZ, a regulatory protein, and increased FAM193B expression. Overexpression in neuroblastoma cells increased DNA damage markers, while postmortem brain data linked gene activity with neuronal-death pathways. These stages examine a proposed biological mechanism; the study tested no repeat-altering treatment in patients.[1]

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References

  1. News sourceNature NeuroscienceA DNA repeat in FAM193B is associated with Alzheimer’s risk↩1↩2↩3↩4
  2. News sourceScienmagHidden DNA Repeats Point to a New Alzheimer’s Risk Gene, Long-Read Study Reveals↩
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