NCDS and the genetics of common diseases

NCDS and the largest ever study of the genetics of common diseases

A recent study carried out by the Wellcome Trust Case Control Consortium has made important breakthroughs in understanding links between people’s genes and some of our most common diseases. DNA of members of the NCDS cohort study has made a vital contribution to this research, which was carried out by a large team of scientists who are experts in a number of health problems. The diseases which have been studied include diabetes, rheumatoid arthritis, Crohn’s disease and coronary heart disease, which together affect many individuals.

The study is known as a genome-wide association study. It involves comparing the DNA of large samples of individuals known to have a disease (i.e. ‘cases’) with large samples of individuals who do not have the disease (i.e. ‘controls’). Two separate control groups were used in the study. One group consists of blood donors who volunteered to take part in the research. The other control group was selected from the members of NCDS who kindly consented to provide a blood sample as part of the biomedical study, and for their DNA to be extracted from that blood for medical research. The use of two control groups is important because it improves the reliability of the results.

The study has found a number of very small but significant differences in the patterns of genes for those in the groups of cases with specific diseases and those in the control groups. For example those with coronary artery disease were found to have a slightly different pattern of genes in a specific region of chromosome nine. However, it is important to remember that these common diseases have complex sets of causes. They are part ‘nurture’ and part ‘nature’. Genes alone do not determine whether you will get a disease such as diabetes. Environment and lifestyle also have a major influence on whether an individual gets a particular disease. However, the significance of the recent research is that by identifying the genes that are linked to conditions, scientists can gain a better understanding of which people are at most risk and how the disease occurs. This in turn may lead to the development of better treatments, improved diagnosis and better disease prevention.

Frequently asked questions

1) Can I get information about my genetic profile from CLS?

No, it was important that when we collected the DNA sample from members of the cohort that we gained consent from you to use the DNA for research purposes, but also guaranteed not to reveal your individual results. This is because knowledge of genetic susceptibility to some diseases may make it difficult for you to get some types of insurance or life cover. It is also important to remember that very few diseases are only linked to genes there is almost always an environmental component too. This means that those who are genetically susceptible to the disease will not necessarily contract the particular disease.

2) How was DNA obtained?

As part of the Biomedical study carried out in 2002-2003, nurses took a small blood sample from cohort members who gave their consent. White blood cells from this blood have been stored to provide a renewable source of DNA for non-commercial research.

3) I don’t remember giving consent for my DNA to be used

Not everyone in NCDS was part of the biomedical survey and of those 9,377 who did take part a total of 8,404 gave consent to their DNA being used. It therefore may well be that you are in the study but that we do not hold your DNA.

4) Who has access to my DNA?

The samples of DNA from cohort members are only available to those carrying out non-commercial medical research. Any researcher who needs to use the DNA samples must first get clearance for their project from a medical ethics committee. The samples of DNA have all been bar coded with a unique serial number so that the anonymity of cohort members is preserved.

Useful links

For more information about the NCDS biomedical follow-up, please visit the CLS website.

For further information about DNA collection in the biomedical follow-up and analysis of genetic data arising from the project, please consult the following website: www.b58cgene.sgul.ac.uk. This is quite technical in places and includes a list of scientific journal articles based on the study under the ‘Other Info’ menu.

If you want to find out more about links between genetics and health the following web sites should be useful.

www.geneticalliance.org.uk
Genetic Interest Group: working to benefit all people affected by genetic disorders

www.nhslocal.nhs.uk/my-health/equip/links/list/health-info
(Site providing useful links to further information about a range of genetic disorders)

National Child Development Study: Members site