A perspective for sequencing familial hypercholesterolaemia in African Americans

African American mothers' attitudes towards genetic testing in the InterGEN study

The paucity of representation of people of color, particularly those of African ancestry, is a major issue in contemporary omics research. Metadata summarizing genome-wide association studies from 2005 to 2015 suggest that nearly 80% of participants are of European ancestry and only 2.4% are of African ancestry. Negative attitude towards genetic testing is a commonly cited belief as to why there is low representation of Americans of African ancestry participating in genetic studies. Using the attitudes towards genetic testing survey, administered as part of our parent (epi)genome-wide association study, we characterized the perceptions of genetic research among our cohort of African ancestry women (n = 168). Our data show generally favorable perceptions of genetic testing among our cohort. Further, we demonstrate that more favorable attitudes towards genetic testing correlated with higher levels of income, even when accounting for commonly cited negative predictors such as maternal age, education, country of origin, and religion. Overall, our data characterize generally positive perceptions of genetic testing among women of African ancestry.

Effects of Genetic Variants Associated with Familial Hypercholesterolemia on Low-Density Lipoprotein-Cholesterol Levels and Cardiovascular Outcomes in the Million Veteran Program

Background

Familial hypercholesterolemia (FH) is characterized by inherited high levels of low-density lipoprotein cholesterol (LDL-C) and premature coronary heart disease (CHD). Over a thousand low-frequency variants in LDLR, APOB and PCSK9 have been implicated in FH but few have been examined at the population level. We aim to estimate the phenotypic effects of a subset of FH variants on LDL-C and clinical outcomes among 331,107 multi-ethnic participants.

Methods

We examined the individual and collective association between putatively pathogenic FH variants included on the MVP biobank array and the maximum LDL-C level over an interval of 15 years (maxLDL). We assessed the collective effect on clinical outcomes by leveraging data from 61.7 million clinical encounters.

Results

We found 8 out of 16 putatively pathogenic FH variants with ≥30 observed carriers to be significantly associated with elevated maxLDL (9.4-80.2 mg/dL). Phenotypic effects were similar for European and African Americans despite substantial differences in carrier frequencies. Based on observed effects on maxLDL, we identified a total of 748 carriers (1:443) who had elevated maxLDL (36.5±1.4 mg/dL, p=1.2×10-152), and higher prevalence of clinical diagnoses related to hypercholesterolemia and CHD in a phenome-wide scan. Adjusted for maxLDL, FH variants collectively associated with higher prevalence of CHD (odds ratio, 1.59 [95% CI 1.36-1.86], p=1.1×10-8) but not peripheral artery disease.

Conclusions

The distribution and phenotypic effects of putatively pathogenic FH variants were heterogeneous within and across variants. More robust evidence of genotype-phenotype associations of FH variants in multi-ethnic populations is needed to accurately infer at-risk individuals from genetic screening.

Biorepository and integrative genomics initiative: designing and implementing a preliminary platform for predictive, preventive and personalized medicine at a pediatric hospital in a historically disadvantaged community in the USA

Current healthcare is evolving to emphasize cost-effective care by leveraging results and outcomes of genomic and other advanced research efforts in clinical care and preventive health planning. Through a collaborative effort between the University of Tennessee Health Science Center (UTHSC) and Le Bonheur Children's Hospital (LBCH), the Biorepository and Integrative Genomics (BIG) Initiative was established to set up a pediatric-based DNA biorepository that can serve as a foundation for successful development of delivery platforms for predictive, preventive, and personalized medical services in Memphis, Tennessee, a historically disadvantaged community in the USA. In this paper, we describe the steps that were followed to establish the biorepository. We focused on domains that are essential for implementation of a biorepository for genomic research as an initial goal and identified patient consent, DNA extraction, storage and dissemination, and governance as essential components. Specific needs in each of these domains were addressed by respective solutions developed by multidisciplinary teams under the guidance of a governance model that involved experts from multiple hospital arenas and community members. The end result was the successful launch of a large-scale DNA biorepository, with patient consent greater than 75% in the first year. Our experience highlights the importance of performing pre-design research, needs assessment, and designing an ethically vetted plan that is cost-effective, easy to implement, and inclusive of the community that is served. We believe this biorepository model, with appropriate tailoring according to organizational needs and available resources, can be adopted and successfully applied by other small- to mid-sized healthcare organizations.

Population specific genetic heterogeneity of familial hypercholesterolemia in South Africa

PURPOSE OF REVIEW

To describe the prevalence and population-specific genetic heterogeneity of familial hypercholesterolemia in South Africa.

RECENT FINDINGS

This review highlights the paucity of data on familial hypercholesterolemia in South Africa, and the urgent need to uncover the mutation profiles in lipid-associated genes, causing an increase in LDL-cholesterol in the different ethnic groups. Case reports and small studies have shown that familial hypercholesterolemia, although apparently uncommon, is present in black Africans.

SUMMARY

Local founder effects have led to an increased prevalence of familial hypercholesterolemia in several South African populations: Afrikaner founder mutations (c.681 C>G, c.1285 G>A, c.523 G>A), Ashkenazi founder mutation (c.654_656del) and possible Indian founder mutation (c.2054 C>T). Preliminary data in black Africans with elevated LDL-cholesterol identified a possible common mutation, c.137_142del. The South African multiethnic society and well described founder effects emphasize the need for differential approaches to diagnosis and management of familial hypercholesterolemia. Studies involving larger cohorts and inclusive of different ethnicities are paramount to establishing an accurate prevalence of familial hypercholesterolemia in black Africans, not only in South Africa but in the Sub-Saharan African region. It is clear that the estimated world prevalence of one in 250 cannot be generally applied across African populations.

Joint Influence of SNPs and DNA Methylation on Lipids in African Americans From Hypertensive Sibships

INTRODUCTION

Plasma concentrations of lipids (i.e., total cholesterol, high-density cholesterol, low-density cholesterol, and triglycerides) are amenable to therapeutic intervention and remain important factors for assessing risk of cardiovascular diseases. Some of the observed variability in serum lipid concentrations has been associated with genetic and epigenetic variants among cohorts with European ancestry (EA). Serum lipid levels have also been associated with genetic variants in multiethnic populations.

METHODS

The purpose of this study was to determine whether single-nucleotide polymorphisms (SNPs) and DNA methylation (DNAm) differences contribute to lipid variation among African Americans ([AAs], N = 739) in the Genetic Epidemiology Network of Arteriopathy (GENOA) study.

RESULTS

Previous meta-analyses identified 161 SNPs that are associated with lipid traits in populations of EA. We evaluated these SNPs and 66 DNAm sites within the genes containing the SNPs in the GENOA cohort using linear mixed-effects modeling. We did not identify any significant associations of SNPs or DNAm with serum lipid levels. These results suggest that the SNPs identified as being significant for lipid levels through the EA genome-wide association studies may not be significant across AA populations.

CONCLUSIONS

Reductions in morbidity and mortality due to variation in lipids among AAs may be achieved through a better understanding of the genetic and epigenetic factors associated with serum lipid levels for early and appropriate screening. Further large-scale studies specifically within AA and other non-EA populations are warranted.

Genome Sequencing Technologies and Nursing: What Are the Roles of Nurses and Nurse Scientists?

BACKGROUND

Advances in DNA sequencing technology have resulted in an abundance of personalized data with challenging clinical utility and meaning for clinicians. This wealth of data has potential to dramatically impact the quality of healthcare. Nurses are at the focal point in educating patients regarding relevant healthcare needs; therefore, an understanding of sequencing technology and utilizing these data are critical.

AIM

The objective of this study was to explicate the role of nurses and nurse scientists as integral members of healthcare teams in improving understanding of DNA sequencing data and translational genomics for patients.

APPROACH

A history of the nurse role in newborn screening is used as an exemplar.

DISCUSSION

This study serves as an exemplar on how genome sequencing has been utilized in nursing science and incorporates linkages of other omics approaches used by nurses that are included in this special issue. This special issue showcased nurse scientists conducting multi-omic research from various methods, including targeted candidate genes, pharmacogenomics, proteomics, epigenomics, and the microbiome. From this vantage point, we provide an overview of the roles of nurse scientists in genome sequencing research and provide recommendations for the best utilization of nurses and nurse scientists related to genome sequencing.