Alzheimer’s disease develops slowly and involves many biological changes that begin long before clear symptoms appear. Because of this complexity, researchers are increasingly focused on finding early molecular signals that could help improve diagnosis and guide intervention.

Researchers at Universidad del Valle, Colombia used RNA sequencing to study gene activity in blood samples from people with Alzheimer’s disease and cognitively healthy adults. This region is notable for its high genetic diversity and has been historically underrepresented in genomic research, making the findings especially important for broadening our understanding of Alzheimer’s biology across populations.

The team analyzed blood samples from 41 participants, including 14 individuals diagnosed with Alzheimer’s disease and 27 healthy controls. Using high-depth RNA sequencing, they measured which genes were more or less active between the two groups. The analysis uncovered nearly 400 genes that showed altered expression in people with Alzheimer’s disease, with most of these genes showing increased activity.

Several of the altered genes were linked to protein metabolism, including well-known Alzheimer’s-related genes such as APOE. Other genes were associated with how nerve cells communicate at synapses, the specialized junctions where signals are passed between neurons. Changes in these pathways suggest that Alzheimer’s disease involves both disrupted energy and protein handling in the body, as well as altered signaling processes that are critical for memory and cognition.

To connect molecular changes with real-world outcomes, the researchers combined gene expression data with cognitive and functional assessments. This integrated analysis revealed distinct molecular patterns that tracked with worse cognitive performance and daily functioning. These results support the idea that blood-based molecular signals can reflect brain-related changes occurring during Alzheimer’s disease.

Importantly, by focusing on a diverse Latin American cohort, the study highlights the need to move beyond primarily European-ancestry datasets. Expanding RNA sequencing research to underrepresented populations can help ensure that future biomarkers and diagnostic tools are accurate and inclusive, supporting earlier detection and more precise approaches to Alzheimer’s care.