Cognitive decline caused by damage to the brain's blood supply, the second most common cause of dementia. A variant near a gene called SYK was not just statistically associated with it — a laboratory experiment showed the risk version actually changes how a gene's message gets edited.
Vascular dementia is cognitive decline caused by damage to the blood vessels supplying the brain — sometimes a series of small strokes, sometimes a slower narrowing of small vessels over years — rather than by the protein deposits at the centre of Alzheimer's disease. It is the second most common cause of dementia overall, and the two conditions frequently occur together in the same person.
The study behind this page combined a genome-wide association study with literature-based and network analysis to prioritise the most promising candidate gene, and the strongest signal that emerged pointed to SYK, spleen tyrosine kinase. Within the gene, rs290227, an intronic variant, was the most significant finding.
What sets this study apart is what came next. Rather than stopping at the statistical association, researchers used computational analysis to predict that this variant could alter alternative splicing — the process by which a gene's initial RNA message is edited, with some pieces (introns) removed and the remaining pieces (exons) joined, before it becomes a working protein. They predicted the risk variant could cause exon 8 to be skipped or exon 9 to be truncated. Then they tested that prediction directly, building a minigene assay — a laboratory construct containing the relevant piece of DNA — and watching what actually happened. The risk version of the DNA (the G allele) measurably caused delayed and aberrant splicing, exactly as predicted. That is a mechanism demonstrated experimentally, not only inferred from a statistical association.
Diagnosis combines a clinical history — often a stepwise pattern of decline, sometimes following recognised strokes — with cognitive testing and brain imaging (MRI or CT) showing vascular damage: small strokes, or changes in the brain's white matter consistent with narrowed small vessels. None of this depends on a genotype.
What actually reduces vascular dementia risk. The same factors that damage blood vessels elsewhere in the body — high blood pressure, smoking, diabetes, high cholesterol — are the established, modifiable risk factors for vascular dementia, and managing them is the primary prevention strategy. Nothing on this page changes that advice, and the variant here is not used to guide it.
Showing that a variant alters splicing in a laboratory assay is stronger evidence than a statistical association alone, but it is still a step short of showing how altered SYK splicing actually contributes to vascular dementia in a living brain — that connection is inferred, not directly observed. SYK has roles in immune cell signalling, which is a plausible link to inflammation in vascular disease, but this study's own evidence is about the splicing mechanism, not about that downstream biology.
What a 23andMe/AncestryDNA export or raw VCF can and can't tell you about Vascular Dementia comes down to these specific, well-studied positions — not a diagnosis.
Databases, guidelines and references
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Vascular Dementia. MyGeneLog™. https://www.mygenelog.com/conditions/vascular-dementia
No. This is a single locus from one study, and the study does not establish a validated risk figure for individual prediction. Managing blood pressure, diabetes, smoking and cholesterol remains the established way to reduce risk.
The researchers did not stop at a statistical association. They predicted, using computational analysis, that the variant would alter RNA splicing, then built a laboratory construct and directly observed the risk version of the DNA causing delayed, aberrant splicing — a mechanism shown experimentally rather than only inferred.
It means a variant in SYK is associated with vascular dementia risk and has a demonstrated effect on how the gene's RNA is processed. How that splicing change actually contributes to disease in a living brain is not shown by this study and remains an open question.
Manage the vascular risk factors with the strongest evidence behind them: blood pressure, blood sugar, smoking and cholesterol. Those remain the primary, modifiable drivers of vascular dementia risk, and nothing on this page changes that advice.
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