Why Diversity Matters in Rare Disease Biospecimen Research

Photo credit: https://blogs.cdc.gov/genomics/2019/04/04/introducing-the-rare-diseases/

Precision medicine depends on understanding how genetic variation, ancestry, environmental exposures, and social factors interact. Together, these factors shape disease risk, symptoms, and treatment response. But rare disease biospecimen repositories and research cohorts have historically been demographically and genetically narrow. They’ve drawn mostly from people of European ancestry living in cities with access to major academic medical centers. This lack of diversity isn’t just a matter of research equity. It limits what we can learn about rare disease biology. It also weakens how well findings generalize, and risks creating gaps in how effective and accessible new therapies are across different populations.

About 95% of rare diseases still lack an approved therapy. Equity in rare disease research remains a persistent challenge, since non-Caucasian populations stay underrepresented in clinical trials and genetic studies. Rare disease treatment is moving toward gene therapies, precision diagnostics, and biomarker-guided care. As it does, this representation gap will only matter more — unless researchers take deliberate steps to diversify biospecimen collection and research participation.

The Genetic Architecture of Rare Disease Diversity

Rare disease genetic variation clusters in clear patterns across populations, geography, and ancestry. Founder effects, population bottlenecks, consanguinity rates, and migration patterns have all shaped which disease-causing variants show up where.

The specific mutations behind a rare disease often differ across populations too — not just how common the disease is. That affects how the disease presents, how severe it is, and how well it responds to treatment. A gene therapy designed and tested in a homogeneous group may work less well in patients who carry population-specific variants more common in other ancestry groups. Likewise, a diagnostic test validated only in one population may be less sensitive or specific when used in a more genetically diverse group.

Because rare disease genetic variation clusters by population, biospecimen repositories have both a scientific and ethical obligation to reflect human diversity. Researchers studying genotype-phenotype relationships need access to diverse immune and cellular materials. These include PBMCs, CD3+ T cells, and NK cells — materials that represent the full range of relevant mutations.

Phenotypic Heterogeneity Across Populations

Genetic variation is one obvious driver of population-level differences in rare disease. But phenotypic differences across populations also reflect environmental exposures, diet, healthcare access, and epigenetic factors that shape how a disease is expressed.

Research into gene-environment and modifier interactions often relies on multiple specimen types, including whole blood, serum, and plasma. These materials let researchers connect circulating biomarkers to clinical symptoms across different populations.

Rare diseases with an inflammatory or immune-mediated component can also look different across populations, due to variation in immune pathways. Tissue-level studies using skin punch biopsy samples or inflammatory matrices like synovial fluid help identify disease mechanisms that are specific to certain populations.

Biomarker Validation Requires Population Diversity

Taking a biomarker from discovery to clinical validation means proving it performs reliably across the populations it’s meant to serve. A diagnostic biomarker validated only in a narrow population may be less accurate elsewhere, simply due to normal biological variation between groups.

Thorough validation studies often need large sample volumes, such as bulk plasma collections alongside matched plasma and serum samples across ancestry groups. These support building reference ranges and testing how well an assay performs.

Diversity matters even more for predictive biomarkers used to guide treatment choices. If a validation study lacks representation, it risks producing clinical decision tools that work well for some populations and poorly for others.

Addressing Systematic Barriers to Diversity in Biospecimen Collection

Diverse populations are underrepresented in research for several overlapping reasons: geography, financial constraints, and historical mistrust of research institutions. Direct-to-patient collection programs, multilingual outreach, and partnerships with community health centers all help address these barriers.

Mobile collection programs bring advanced cellular collection — including leukopak products — to people outside traditional academic centers, helping ensure diverse immune cell representation.

Genetic Counseling and Return of Results Considerations

As rare disease biospecimen research increasingly uses whole-genome sequencing and advanced molecular analysis, questions about returning results and genetic counseling get more complex. Different communities have different views on predictive genetic information and incidental findings.

Diverse genomic datasets built from cellular collections such as PBMCs and immune subsets improve how accurately variants are interpreted across populations. They also reduce misclassification in global databases.

Precision Medicine Requires Precision in Population Representation

Precision medicine promises therapies tailored to a person’s genetic profile and disease subtype. Delivering on that promise requires biospecimen resources that represent genetic and phenotypic diversity.

Therapeutic development increasingly relies on immune characterization workflows. These workflows combine PBMC isolation, subset purification such as T cells and NK cells, and translational biomarker measurement in plasma or serum.

Creating Inclusive Research Ecosystems

Closing diversity gaps requires systematic change across research infrastructure, funding priorities, and institutional culture. Biospecimen repositories need to actively track the demographics of their collections. They should pursue recruitment strategies aimed at real representation goals, rather than simply accepting whoever is easiest to reach.

From Study Design to Receipt of Samples: Building Equitable Biospecimen Infrastructure

Building representative rare disease biospecimen resources takes intentional planning from the earliest stages of a study. Inclusion criteria, recruitment strategies, and participant compensation policies all need to be checked for bias.

Sanguine’s direct-to-patient collection infrastructure supports nationwide recruitment and enables diverse participation, while maintaining rigorous quality standards from study design to receipt of samples.