Faqs
FAQ about volunteering
1. Why take part in research?
Why are twins of such great value to health research?
- Our health and how we age is mostly determined by a combination of our unique genetic makeup (nature) and our environment such as lifestyle and life experiences (nurture). The genes of identical twins are 100% the same so comparing them with non-identical twins, who share only 50% of their genes, allows us to separate the genetic and environmental factors, and enables researchers to accurately measure the effects of our environment and life-style on our health.
- Our research using the DNA of twin research volunteers and the data from twin visits and questionnaires has led to a number of important research discoveries and projects:
- We have been able to work out how much our genes influence common traits and diseases. For example, we have discovered that many common diseases of ageing (such as Type 2 diabetes and osteoarthritis) are, for most people, caused more by life-style and life-experience than by genes.
- We have also been able to pinpoint the specific genes that contribute to the development of disease such as type 2 diabetes, melanoma and osteoporosis.
- Our work on healthy ageing and frailty is aiming to identify new ways to predict and prevent frailty so that we can all age as healthily as possible
- Our work on the microbiome (the bacteria that live inside us) is revealing important insights into how our health and immune system are closely linked to the bacteria that live in our guts.
What does the research process look like?
Carrying out a research study takes months, sometimes years of preparation and research, funding applications and ethics approval. The first step is the conception of an original research idea that can be effectively carried out in a research setting and will yield results that have the potential to contribute to our understanding of the body and how it works. To see the whole research process explained in detail, please click here to go to Study Life Cycle page
What are the benefits of participating?
Apart from contributing to important health research that will improve our knowledge of complex disease and how to treat them, taking part in research can also benefit you by allowing you to have a full health MOT at your twin visit. We are able to provide you with clinically useful results for some of the tests.
2. The practicalities of taking part in research
How often are volunteers asked to come for a twin visit?
Currently we are inviting twin volunteers to come for a visit approximately once every four years. This timeline enables us to see most of the twins on our registry, tracking valuable health changes with time. In between twin visits we rely on the data collected in online-postal questionnaires to keep us up to date. If you are a member of TwinsUK and have not been in for a visit for about four years, or would like to join the registry, please call 0207 188 5555 to arrange a visit.
I would like to take part in a study but I cannot come in to the DTR; can I still take part?
Yes, although the twin visit provides very valuable data, our questionnaires also give us an enormous amount of information for use in research. There are also some studies which you can do from home for example, saliva and hair samples can be collected via post as we can extract DNA from these samples for use in research. We may also ask for twins to donate blood through their GP and post the sample to us.
I live abroad; can I still take part in studies?
Yes, you can still make a valuable contribution by taking part by completing our online questionnaires.
Will you cover my expenses?
Travel: Yes, you will be eligible to have some or all of your transport costs covered. Due to being charity-funded we do ask volunteers to book their travel as far in advance as possible and by the cheapest means possible. When you book your visit, the admin team will provide you with more information.
Daily expenses – Regrettably because we are a charity-funded organisation, we are unable to cover work expenses so we rely on the good will of volunteers to kindly donate their valuable time for the benefit of research.
Accommodation – The provision of over-night accommodation close to St Thomasâ depends on where you live. When you book your visit, the admin team will provide you with more information.
Can I come for a twin visit at the weekend?
Sorry, no. Currently the Department is only open Monday to Friday.
I have special needs can I participate?
Yes. Please call us on 020 7188 5555 to discuss your needs so we can accommodate your requirements. In addition, our research facility is accessible by lift and is wheelchair accessible. There are disabled toilets throughout the hospital.
Can my carer come with me?
Yes. Please let us know when you book your appointment.
Will I be able to take part in any publicity?
From time to time we hold media / publicity events / press conferences or take part in documentaries. Alternatively, we may be approached by third parties who are interested in contacting twins. We never give your personal details out but will always contact you directly (usually via email) to ask if you are interested in taking part.
Can I join the registry without my twin?
In order to determine the relative importance of genetic and environmental factors, researchers need to compare identical twins with non-identical twins for the trait of interest. For this reason we are sorry but we need both twins to join the registry together.
Can I come on a twin visit without my twin?
In order to determine the relative importance of genetic and environmental factors, researchers need to compare identical twins with non-identical twins for the trait of interest at the same time point- however in some circumstances you and your twin can come at different times for a twin visit. Lone twins who previously took part in our research together are invited to continue coming on visits alone as they are still able to contribute valuably to the research.
Can I complete a questionnaire even if my twin doesnât?
Yes! Although we would rather have both of you participating, your questionnaire data will still be useful.
How does the Department of Twin Research keep in touch with twins?
We will normally call you or email you and we also send texts from time to time. We may also write to you or send you questionnaires, so it is important for us to have your up-to-date contact information. You will also receive an annual newsletter and enewsletters throughout the year which will keep you informed of our research findings and studies. Finally, you can find us on facebook, twitter and YouTube with regular updates and feeds.
What happens if I join the registry but then wish to withdraw?
You are free to withdraw at any stage without any explanation. If you withdraw, you would have no further contact from the Department of Twin Research unless you request our newsletter only.
You can withdraw by contacting the Admin Team on 020 7188 5555
(Mon-Fri 9-5pm)
or by emailing us on twinsuk@kcl.ac.uk
or alternatively writing to:
The Admin Team,
Department of Twin Research,
St. Thomasâ Hospital,
Westminster Bridge Road,
London,
SE1 7EH.
If at any time you wish to rejoin the registry we will be happy to reactivate your records. Please see Question 3 to find out what happens to your data and samples after you withdraw.
3. Data & Samples
What happens to the data & samples you collect?
All clinical measurements, questionnaire data and biological samples including DNA will be stored centrally and securely. We will ensure that all personal data and results are anonymised and cannot lead to the identification of a single individual.
What happens to my samples after I donate them?
Immediately after collection, blood is centrifuged and separated into various components such as serum, plasma and white cells. Part of the serum and all plasma samples are stored in freezers at a low temperature. Other components are sent for glucose, lipids, and cholesterol tests. From the white cells we extract and store the DNA, which is essential for all our research.
How do you use the DNA?
Some of the DNA is stored, and some of the DNA is analysed so that researchers can make associations between people with certain conditions such as osteoporosis and the presence or absence of certain genetic variations. The researchers look for differences in the members of the TwinsUK registry as a whole, but not as individuals.
Because our health is made up of the interaction of thousands of genes with numerous life-style factors, currently we are unable to obtain any clinically useful genetic information from just one person. Ultimately we hope to find the genes that may be responsible for many of our common diseases.
Will DNA be used in cloning experiments?
Your DNA will NOT be used for any experiments with regard to human cloning.
Do I have to donate blood for DNA?
The premise of twin studies is the identification of genetic similarities or differences between twins. For this reason, donating blood for DNA extraction is an essential part of our research. Giving blood for DNA is of course voluntary, but you may not be able to carry on participating in the majority our research if you decide not to.
What happens to my data & samples if I withdraw?
If you decide to withdraw, your previously collected samples and data cannot be removed or destroyed because of the complex nature in the way anonymised data and samples are stored and distributed. All your personal information will be held for archival purposes only and we will continue to preserve confidentiality and security of this data.
4. Research Results
What results will I receive?
Our twin research programme aims to discover the genetic and environmental basis of age-related complex disease and traits, and is not a clinical testing programme. Some of the information and data that we collect at the visit is of no clinical significance as it is still in the research phase (such as the flora âstool sampleâ study). This means that we do not yet know the significance of the results, and at present neither we, nor your GP, would be able to interpret them. This is summarised on our research consent form as follows âthe results of these investigations are unlikely to have any implications for me personallyâ. However, we are happy that we have received ethics approval to give you a set of clinically useful results for you and your GP from some of the tests that we undertake â including blood pressure, bone density, general blood tests, glucose, cholesterol and renal and liver function tests. You will receive these results between 4 and 6 weeks after your visit. An example of a results letter can be seen by CLICKING HERE. In addition, you will get verbal feedback/advice for some of the tests such as the eye test, grip strength test and lung function test.
Will I receive Genetic results?
At present, we cannot provide you with genetic information, because the laboratories where our research takes place are not certified to provide clinical genetic information. Typically a clinical laboratory would examine an individual sample for one specific gene, whilst our research laboratory analyses thousands of variations across the genome. The researchers look for differences in the members of the TwinsUK registry as a whole, but not as individuals.
5. Ethical standards and confidentiality
Is the research approved?
Yes. All our research is ethically and scientifically approved by the London â Westminster NRES Committee who examine all research applications to ensure the research is ethical and safe for volunteers. You will also receive an approved Volunteer Information Sheet and a Consent form for every study you take part in. Please feel free to discuss the research with friends, family or your GP if you wish to do so. If there is anything that is not clear or if you would like to have more information we will be happy to discuss this with you.
How are you funded?
We are funded via grants from many organisations and charities including the Wellcome Trust, National Institute for Health Research (NIHR), European Commission, Medical Research Council (MRC) and Chronic Disease Research Foundation (CDRF). Smaller projects may be funded by commercial organisations who offer valuable expertise and resources for researchers.
Will you make money from our data?
The Department occasionally collaborates with commercial companies to share expertise. In the rare event of any commercial profits, funds will come back to the hospital and the university for the purpose of further advancement of research.
Who else has access to my personal information / data?
Other approved academic centres and commercial companies – who are collaborating with us in our research – may request access and have rights to the data, including DNA, that we have collected. However, data that is shared is always anonymised.
Are all research collaborators bona fide scientists?
Yes. The anonymised resource is only available to bona fide researchers and access is strictly controlled by a dedicated team of medical and research experts at the Department of Twin Research (DTR) Senior Management Group who assess the potential benefits of the proposed research projects before entering into a legal agreement with the collaborator. On approval, the anonymised data and samples are released to researchers. All researchers are then required to publish their findings and return any valuable results to the DTR so they are available for other scientists to use.
Who owns the data?
The data/intellectual property collected as a result of your participation will always reside with the Hospital and Kings College London. You will not have claim to either the material that we collected or the results arising from the study. Any publications from the twin resource are made available via our website / E-News updates and Annual Newsletter.
Will my taking part in this study be kept confidential?
Yes. We act and comply according to all the principles of the Data Protection Act (1998) and KCL data policies. In summary:
- All information collected about you during the course of the research will be kept strictly confidential. There is a dedicated data management team to ensure that correct procedures are in place at all times.
- Your personal details are kept on a separate database to your clinical and genetic data. A unique participant identifier is used for all clinical and genetic data which is completely anonymous.
- The risks of volunteers being identified inadvertently by researchers is extremely low and is continually reviewed.
Will insurance companies have access to my genetic information?
No. Insurance companies or employers will not have any access to information or samples collected from you. All data is stored centrally in an anonymised database that can only be accessed with passwords. The Department of Twin Research will be the only institution that will be able to link a study number with your personal details.
Conception & Zygosity
What is Zygosity?
Zygosity is a term used to explain whether twins are identical or non-identical and depends on whether they share half or all their genes with their twin.
What are non-identical (fraternal) twins?
Non-identical twinsâ also known as fraternal or dizygotic (DZ) twins are the result of two separate eggs becoming fertilised by two sperm, resulting in two completely distinct pregnancies in the womb at the same time. On average, these twins will share half (50%) of their genes, just like any other siblings. Two thirds of twins are non-identical and may be same sex or male/female pair. Non-identical twins always have two placentae, although the placentae may appear to be fused into one. Non-identical twins may or may not have the same blood group.
What are identical twins?
Identical or monozygotic (MZ) twins occur when a single fertilised egg splits into two after conception. This happens around the time the fertilised egg is becoming implanted in the womb. These twins will share all (100%) of their genes and for this reason have the same blood type. Only one third of all twins are identical and these pairs are always of the same sex. Monozygotic twins may have one shared placenta or two separate placentae or two fused into one. Therefore, the number of placentae is not an accurate method for determining zygosity.
If a disease is found to be highly heritable and one identical twin has been diagnosed with this disease will the other automatically get it?
Not necessarily â heritability does not directly reflect the genetic risk to an individual. Few diseases are 100% genetic; environmental triggers due to lifestyle usually cause expression of most common diseases for which a person may have a genetic predisposition which is why identical twins do not share all diseases.
Is having twins genetic?
Non-identical twinning has been shown to be hereditary on the motherâs side, but can also be attributed to increasing maternal age or as a result of fertility treatment. Identical twinning does not usually run in families and is thought to happen spontaneously most of the time.
What are mirror-image twins?
Apart from having different fingerprints, approximately 25% of identical twins can appear different in a fascinating way – they may exhibit mirror-image or opposite features. For example, they may have opposite hair whorls, hair partings, birth marks or opposite dominant hands and/or feet. A definitive explanation for mirror-imaging is not known, but some researchers believe that it is related to the fertilised egg splitting later than normal at around 7 days or more.
What are polar body twins?
Sometimes before conception occurs a single unfertilised egg splits into two and is then fertilised by separate sperm. It is not known how many twins fall into this category but on average they share 75% of their genes; more than non-identical but less than identical twins. The cause is unknown.
Is it possible to have identical twins with big height and foot size differences?
We do know that identical twins can differ in height due to differences in the womb. About 60%-80% of height variation is due to genetic factors and 40%-20% is determined by environmental factors, mainly nutrition, leading to differences in stature, including foot size.
Are the children of identical twins genetically half-brothers and sisters?
Yes. Children of identical twins are the same genetically as half-siblings.
Is there a relationship between being a twin and handedness?
Yes, one in four twins is left handed compared to one in twelve of the general population.
Do twins have identical fingerprints?
No. Scientists believe that minor differences arise due to random events during fetal development â the finger tissue comes into contact with the amniotic fluid and other parts of the fetus and uterus leading to the development of different fingerprints.
How can DNA-based methods tell apart identical and non-identical twins?
The only 100% certain way of determining whether twins are identical or not is by full-scale genotyping (where a large amount of DNA is âreadâ). However, this is a very expensive process, so the next most reliable test is genetic finger-printing, a DNA test, which looks at 10 -16 variable gene markers and is 99% accurate in determining zygosity. By comparing these genetic markers within a twin pair it is possible to determine whether twins are monozygotic or dizygotic from the similarities or differences between these regions (illustrated below).
How can questionnaire-based methods tell apart identical and non-identical twins?
When DNA-based methods are not available or too expensive, many researchers rely on a âpeas-in-the-podâ (PPQ) zygosity questionnaire that asks about similarities during childhood. This questionnaire consists of 5 short questions and has been shown to give a 95% level of accuracy. As mentioned previously, the number of placentae at birth is not an accurate method to determine zygosity as identical twins can have two placentae.
How will our zygosity be confirmed when we register?
When DNA-based methods are not available or too expensive, many researchers rely on a âpeas-in-the-podâ (PPQ) zygosity questionnaire that asks about similarities during childhood. This questionnaire consists of 5 short questions and has been shown to give a 95% level of accuracy. As mentioned previously, the number of placentae at birth is not an accurate method to determine zygosity as identical twins can have two placentae.
How do I arrange a Twin DNA Zygosity Test?
If you are interested in a private Twin DNA Zygosity test you can contact the Multiple Births Foundation (MBF) on 020 3313 3519, or email info@multiplebirths.org.uk for an application pack or visit their website You will receive the results within 4-6 weeks. However, if we already have a blood sample from you then we are able to have this test carried out for you for a small fee. Please note there will be a considerable wait for the results as we only process the samples approximately once a year as they are outsourced to a private laboratory in a large batch.
Understanding Research Terminology
What is Heritability?
Heritability â is the contribution of genetic differences for a particular trait e.g. heritability for height is around 90%. It means that most of the height difference among individuals is due to the genetic differences.
What is a Phenotype?
Phenotype is a physical or behavioural characteristic of an individual that is influenced by genes and environment such as height, eye colour, hair colour, or blood group. It is these expressed or visible traits and measurements that are collected by scientist for research analysis.
What is a Genotype?
Genotype refers to the genetic make-up of a cell (letters of the DNA) containing instructions. It is determined by employing biotechnology methods called âgenotypingâ to see which genes are present on the different versions of the same gene inherited from each parent (these different versions are called alleles).
What is an Allele?
Different versions of the same gene are called alleles and they can either be recessive or dominant. An individual can have the same (homozygous) allele or two different (heterozygous) alleleâs, one inherited from each parent. For example, the gene for eye colour has an allele that codes for brown eye colour (dominant) and an allele that codes for blue eye colour (recessive). Therefore, both recessive alleles are needed to give blue eye colour whereas only one copy of the dominant allele is needed to give brown eyes.
What is the difference between genotyping and sequencing?
Genotyping is the technical process used for determining genetic make-up of an Individualâs DNA profile. Researchers examine differences in a selection of DNA to understand disease variation.
DNA sequencing is the mapping of our genetic information in greater detail to determine the exact sequence of a certain length of DNA. This technology is being used to identify rarer genetic variations which may be strongly associated with multiple conditions and a personâs susceptibility to developing a wide range of diseases.
What is Genetic Predisposition?
A genetic predisposition (sometimes also called genetic susceptibility) is an increased likelihood of developing a particular disease based on a person’s genetic makeup. A genetic predisposition results from specific inherited genetic variations.
What is Genetic variant?
Genetic variation refers to genetic differences both within and among populations.