Proposed article structure
For this topic, a clinically appropriate structure is: clinical background and unmet need; study design and genome-first approach; major results on prevalence, LDL-C burden, and myocardial infarction risk; interpretation of variant classification disparities; implications for practice, screening, and equity; limitations and future directions; funding and citation details. This structure emphasizes both cardiovascular relevance and the translational genetics issues central to the study.
Highlights
Pathogenic familial hypercholesterolemia variants were similarly prevalent in African ancestry and European ancestry participants, at 1 in 306 and 1 in 273, respectively.
Among carriers of pathogenic variants, the associated LDL-C increase was 20.81 mg/dL greater in African ancestry individuals than in European ancestry individuals.
Variants of uncertain significance were significantly more common in African ancestry participants and, in this group, were associated with higher LDL-C and increased myocardial infarction risk.
The findings support the concern that current variant classification systems, built largely from European-ancestry data, may contribute to underdiagnosis of familial hypercholesterolemia in African ancestry populations.
Background and clinical context
Familial hypercholesterolemia (FH) is one of the most important inherited cardiovascular conditions encountered in clinical medicine. It is characterized by lifelong elevation of low-density lipoprotein cholesterol (LDL-C), accelerated atherosclerosis, and increased risk for premature coronary artery disease and myocardial infarction. In many patients, the phenotype is driven by pathogenic variants in genes affecting LDL receptor function and cholesterol handling, most commonly LDLR, APOB, and PCSK9. When untreated, heterozygous FH substantially raises lifetime risk of atherosclerotic cardiovascular disease, yet early recognition and statin-based treatment can dramatically modify prognosis.
Despite the major public health importance of FH, the evidence base that informs prevalence estimates, diagnostic algorithms, and variant interpretation has been heavily weighted toward individuals of European ancestry. That imbalance has practical consequences. If genetic reference databases and curated pathogenicity frameworks are less informative for underrepresented populations, then the same biological disease may be less likely to receive a definitive molecular label in those groups. In turn, patients may miss cascade screening, intensive LDL-C lowering, and recognition of elevated coronary risk.
The study by Winters and colleagues addresses this gap through a genome-first framework. Rather than beginning with clinically suspected FH cases, the investigators started with large biobank-based populations, classified variants using Clinical Genome Resource standards, and then examined lipid levels and myocardial infarction outcomes across African and European ancestry groups. This design is especially useful for detecting hidden disease burden and for revealing where current variant interpretation systems may fail.
Study design
Population and cohorts
This was a multi-cohort, genome-first analysis including 104,300 African ancestry individuals drawn from 3 US-based cohorts: the National Institutes of Health All of Us Research Program, Mount Sinai’s BioMe, and Geisinger’s MyCode. European ancestry comparators were also analyzed within the same framework. Ancestry assignment was based on genetic similarity to reference populations rather than self-report alone, an important methodological choice for genomic analyses.
Variant assessment
Genetic variants relevant to FH were evaluated using standards from the Clinical Genome Resource’s FH Variant Curation Expert Panel. Variants were grouped into pathogenic variants and variants of uncertain significance (VUSs). This distinction is central to the study. Pathogenic variants meet accepted evidence thresholds for disease causality, whereas VUSs lack sufficient evidence for definitive classification. In practice, VUSs often create diagnostic uncertainty and can expose ancestry-related inequities in genomic medicine when evidence is sparse in certain populations.
Outcomes
The main clinical outcomes were LDL-C and myocardial infarction. Analyses were adjusted for age and sex, and results were meta-analyzed across the 3 cohorts. The abstract does not specify all details regarding medication adjustment, ascertainment of peak versus observed LDL-C, or event adjudication, so these points remain important when judging the absolute effect sizes.
Key findings
Prevalence of pathogenic FH variants was similar across ancestries
The prevalence of a pathogenic FH variant was 1 in 306 among African ancestry participants and 1 in 273 among European ancestry participants. This is a clinically important finding because it challenges any lingering assumption that genetically mediated FH is substantially rarer in African ancestry populations. At a population level, the burden appears broadly similar.
For clinicians and health systems, this result argues against under-screening of African ancestry patients on the assumption of lower inherited risk. If anything, the data suggest that the disease may be equally common but less readily recognized when variant evidence is incomplete.
Pathogenic variants were associated with greater LDL-C elevation in African ancestry individuals
Among carriers of pathogenic variants, the LDL-C elevation was 20.81 mg/dL greater in African ancestry individuals than in their European ancestry counterparts, with a 95% confidence interval of 16.17 to 25.45 mg/dL. This is a notable effect size. It suggests that once a clearly pathogenic FH genotype is present, the phenotypic expression in terms of LDL-C burden may be even more pronounced in African ancestry participants.
Several explanations are possible. These include biological modifiers, environmental exposures, differences in treatment intensity or access, survivorship effects, and ascertainment patterns. The study abstract does not allow firm conclusions on mechanism, but the signal is clinically meaningful because LDL-C burden across the life course is a major determinant of atherosclerotic risk.
VUSs were more common in African ancestry participants
African ancestry individuals had 1.61-fold higher odds of carrying a VUS than European ancestry individuals, with a 95% confidence interval of 1.42 to 1.83 and a P value of 1.2×10-12. This is one of the most important findings in the study. It reflects the well-recognized reality that genomic databases and pathogenicity frameworks remain less complete for non-European populations.
From a practical standpoint, a higher VUS burden means more ambiguous genetic reports, less confidence in diagnosis, and potentially fewer patients qualifying for a formal molecular FH label. Since many care pathways, family screening efforts, and specialist referrals are influenced by genetic certainty, this ambiguity can become a direct contributor to inequitable care.
VUSs in African ancestry individuals tracked with more severe lipid phenotype
Compared with European ancestry individuals carrying a VUS, African ancestry individuals with a VUS had a 10.01 mg/dL greater elevation in LDL-C, with a 95% confidence interval of 6.13 to 13.88 mg/dL. This finding is highly suggestive. Although these variants remain formally unclassified, their association with a more adverse LDL-C phenotype in African ancestry patients raises the possibility that at least some are truly disease-relevant variants that current systems fail to recognize as pathogenic or likely pathogenic.
In other words, the label “uncertain” may partly reflect evidence gaps rather than true biological uncertainty. This distinction matters. A VUS should not automatically drive management as if pathogenic, but when a VUS consistently tracks with marked hypercholesterolemia and adverse cardiovascular outcomes in an underrepresented population, it becomes a signal that reclassification efforts are urgently needed.
Myocardial infarction risk was elevated with pathogenic variants in both ancestry groups
Pathogenic variants conferred a 2- to 3-fold increased risk of myocardial infarction in both African and European ancestry groups. This is fully consistent with the established biology of FH and reinforces the validity of the genome-first approach. It confirms that the identified pathogenic genotypes carry clinically important coronary consequences across ancestry groups.
Although the abstract does not provide the exact ancestry-stratified odds ratios for pathogenic variants, the broad magnitude aligns with prior literature showing substantial excess coronary risk in genetically defined FH, particularly when untreated or undertreated over decades.
VUSs carried myocardial infarction risk in African ancestry individuals
Perhaps the most striking result is that a VUS was associated with increased myocardial infarction risk only in the African ancestry group, with an odds ratio of 1.91 and a 95% confidence interval of 1.18 to 3.10. That level of risk approached the risk seen with pathogenic variants. This finding strongly supports the authors’ conclusion that dependence on existing variant classification resources may underdiagnose FH in African ancestry populations.
Clinically, the result should not be overread to mean that every VUS in every African ancestry patient should be treated as pathogenic. However, it does mean that an “uncertain” result in a patient with markedly elevated LDL-C, premature family coronary disease, or suggestive physical findings should not be dismissed as benign noise. The phenotype still matters, and this study shows that in African ancestry populations, some VUSs may be acting as hidden pathogenic variants within current classification systems.
Clinical interpretation
Why the genome-first design matters
Traditional FH studies often begin with patients who are clinically recognized, referred, or already flagged by lipid clinics. That design can miss patients who lack access to specialty care or whose disease is not recognized because of ancestry-linked diagnostic blind spots. A genome-first strategy works in the opposite direction: identify individuals with relevant variants in large populations, then examine phenotype and outcomes. This is particularly valuable for studying underdiagnosis and structural inequities in genomic medicine.
Here, the approach reveals a key paradox. The prevalence of clearly pathogenic FH variants is similar across ancestries, but uncertainty in variant classification falls disproportionately on African ancestry individuals. As a result, the genetically supported burden of FH may be visible in European ancestry populations and partially obscured in African ancestry populations.
Implications for everyday practice
For lipid specialists, cardiologists, internists, and primary care clinicians, the study carries several practical messages. First, suspicion for FH should be the same across ancestry groups when LDL-C levels, personal history, or family history are suggestive. Second, a VUS in an African ancestry patient should be interpreted in the full clinical context, not in isolation. Third, aggressive LDL-C management should continue to be guided primarily by absolute risk and phenotype, especially when genetic ambiguity coexists with severe hypercholesterolemia.
These findings also support broader implementation of cascade screening and more equitable access to specialty lipid evaluation. If a family presents with severe hypercholesterolemia and premature myocardial infarction, the absence of a formally pathogenic classification in one member should not stop thoughtful family-based risk assessment.
Implications for laboratories and guideline development
The study highlights an urgent need for ancestry-diverse variant databases, recontact pipelines for variant reclassification, and evidence frameworks that incorporate population-specific genotype-phenotype information. Laboratories and expert panels may need to prioritize re-evaluation of FH-related VUSs seen disproportionately in African ancestry populations, particularly when supported by LDL-C and coronary event data.
Current FH guidelines from major societies emphasize clinical diagnosis, cascade screening, and early initiation of high-intensity lipid-lowering therapy. This study strengthens the rationale for maintaining a phenotype-first clinical pathway even when genetic interpretation is inconclusive. It also suggests that future guidance should address the inequity created by ancestry-skewed variant evidence.
Strengths and limitations
The study has several clear strengths: very large sample size, inclusion of more than 100,000 African ancestry individuals, multi-cohort design, ancestry assignment using genetic data, standardized variant curation principles, and clinically meaningful endpoints including myocardial infarction. Few FH studies have been positioned to examine these questions at this scale.
Important limitations also deserve attention. The abstract provides limited detail on lipid measurement methods, adjustment for lipid-lowering therapy, socioeconomic confounding, and event ascertainment. Observational biobank studies may also be influenced by selection bias, health system differences, and incomplete phenotyping. In addition, ancestry categories based on genetic similarity are useful for genomic analysis but do not capture the full social and environmental complexity that can influence lipid levels and cardiovascular outcomes.
Another caution is interpretive. Although the association of VUSs with LDL-C elevation and myocardial infarction in African ancestry individuals is compelling, association alone does not prove that each VUS is causal. Some signal may reflect linkage, residual confounding, or heterogeneity among individual variants. Variant-level functional studies and segregation analyses remain essential.
What comes next
The next phase of work should focus on reclassifying ancestry-enriched FH VUSs using integrated evidence: functional assays, family segregation, large-scale genotype-phenotype associations, and diverse reference datasets. Prospective studies should also examine whether ancestry differences in LDL-C expression among pathogenic variant carriers are explained by treatment gaps, modifier genes, diet, access to care, or combinations of these factors.
From a health systems perspective, the study supports investment in equitable genomic infrastructure. That includes more inclusive biobanks, better representation of African ancestry populations in variant databases, and clinical workflows that flag severe hypercholesterolemia for treatment regardless of whether the laboratory report reaches a definitive molecular conclusion.
Conclusion
This genome-first analysis offers an important corrective to the FH literature. Pathogenic FH variants appear similarly prevalent in African and European ancestry populations, but African ancestry individuals are more likely to receive VUS classifications and, critically, those VUSs are associated with higher LDL-C and increased myocardial infarction risk. The overall message is not that FH biology differs categorically by ancestry, but that the precision of our classification systems does.
For clinicians, the study reinforces a simple but consequential principle: do not let uncertainty in variant labeling overshadow a convincing FH phenotype, particularly in African ancestry patients. For researchers and laboratories, it is a call to close the evidence gap that turns true disease into diagnostic ambiguity. For public health, it is evidence that equitable genomic medicine requires not only access to sequencing, but also fair and representative interpretation.
Funding and trial registration
The abstract cites 3 contributing cohorts: the National Institutes of Health’s All of Us, Mount Sinai’s BioMe, and Geisinger’s MyCode. Specific funding details and any ClinicalTrials.gov registration number are not provided in the abstract and should be confirmed from the full publication.
References
Winters AH, Kelly MA, Syed MG, Bergquist T, Berry ASF, Mohammed N, Cawley D, Jones LK, Pejaver V, Gidding SS, Oetjens MT. A Genome-First Study of Familial Hypercholesterolemia Comparing African and European Ancestry Individuals. Circulation. 2026-05-29. PMID: 42212376. Available at: https://pubmed.ncbi.nlm.nih.gov/42212376/
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Santos RD, Gidding SS, Hegele RA, et al. Defining severe familial hypercholesterolaemia and the implications for clinical management: a consensus statement. Lancet Diabetes Endocrinol. 2016;4(10):850-861.
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