Translating genomic analyses into improved management of coronary artery disease

Introducing genetic testing for cardiovascular disease in primary care: a qualitative study

BACKGROUND

While primary care systematically offers conventional cardiovascular risk assessment, genetic tests for coronary heart disease (CHD) are increasingly commercially available to patients. It is unclear how individuals may respond to these new sources of risk information.

AIM

To explore how patients who have had a recent conventional cardiovascular risk assessment, perceive additional information from genetic testing for CHD.

DESIGN AND SETTING

Qualitative interview study in 12 practices in Nottinghamshire from both urban and rural settings.

METHOD

Interviews were conducted with 29 adults, who consented to genetic testing after having had a conventional cardiovascular risk assessment.

RESULTS

Individuals' principal motivation for genetic testing was their family history of CHD and a desire to convey the results to their children. After testing, however, there was limited recall of genetic test results and scepticism about the value of informing their children. Participants dealt with conflicting findings from the genetic test, family history, and conventional assessment by either focusing on genetic risk or environmental lifestyle factors. In some participants, genetic test results appeared to reinforce healthy behaviour but others were falsely reassured, despite having an 'above-average' conventional cardiovascular risk score.

CONCLUSION

Although genetic testing was acceptable, participants were unclear how to interpret genetic risk results. To facilitate healthy behaviour, health professionals should explore patients' understanding of genetic test results in light of their family history and conventional risk assessment.

The association between variants on chromosome 9p21 and inflammatory biomarkers in ethnically diverse women with coronary heart disease: a pilot study

BACKGROUND

The most consistently replicated genetic variants associated with coronary heart disease (CHD) in populations of European descent have been found on chromosome 9p21. Yet there is little known about these associations in ethnic groups of African ancestry. These disease-associated variants are located in a genomic region of unknown function. The purpose of this exploratory study was to examine the allelic frequencies and haplotype structure of single nucleotide polymorphisms (SNPs) for Black and White women with CHD. The authors also sought to explore the relationship between these genetic variants and biomarkers of inflammation.

METHODS

Using polymerase chain reaction amplification, the authors genotyped 8 SNPs in a 58-kilobase region of chromosome 9p21 in a cohort of women with CHD (n = 91). The authors examined the interethnic relationship between the SNPs and four inflammatory biomarkers (C-reactive protein, intercellular adhesion molecule-1, interleukin-6, and tumor necrosis factor-alpha) using analysis of variance (ANOVA).

RESULTS

We found considerable interethnic allelic and haplotype diversity across the 9p21 locus, with only two SNPs in perfect linkage disequilibrium (LD) in both races. A pair of high- and low-risk haplotypes was most common in White women, while about 41% of Blacks carried the risk alleles for three of the eight SNPs the authors examined. The interethnic associations between the SNP genotypes and inflammatory markers were divergent in both direction and magnitude.

CONCLUSIONS

Our results lend support for the importance of ancestry-specific allelic context when examining variants on chromosome 9p21. Additional work is needed to elucidate the genetic contribution to inflammatory biomarkers for diverse racial groups.

The sense and nonsense of direct-to-consumer genetic testing for cardiovascular disease

Expectations are high that increasing knowledge of the genetic basis of cardiovascular disease will eventually lead to personalised medicine—to preventive and therapeutic interventions that are targeted to at-risk individuals on the basis of their genetic profiles. Most cardiovascular diseases are caused by a complex interplay of many genetic variants interacting with many non-genetic risk factors such as diet, exercise, smoking and alcohol consumption. Since several years, genetic susceptibility testing for cardiovascular diseases is being offered via the internet directly to consumers. We discuss five reasons why these tests are not useful, namely: (1) the predictive ability is still limited; (2) the risk models used by the companies are based on assumptions that have not been verified; (3) the predicted risks keep changing when new variants are discovered and added to the test; (4) the tests do not consider non-genetic factors in the prediction of cardiovascular disease risk; and (5) the test results will not change recommendations of preventive interventions. Predictive genetic testing for multifactorial forms of cardiovascular disease clearly lacks benefits for the public. Prevention of disease should therefore remain focused on family history and on non-genetic risk factors as diet and physical activity that can have the strongest impact on disease risk, regardless of genetic susceptibility.