GPs in primary care will be used to patients saying 'I didn't understand what they told me' and expecting clarification of information given during a hospital appointment.
Help is at hand if the patient was seen by a member of the regional clinical genetics service because it is usual for a copy of a letter summarising the consultation to be sent to the patient and their GP.
We have found that drawing diagrams to explain how genes are passed on from parent to child and how this process results in different genetic combinations in children can be helpful (see box below, other examples can be found at www.geneticseducation.nhs.uk).
It can be helpful to discuss the two components of genetic 'risk' as perceived by patients - the mathematical probability of recurrence and the 'burden' of the disease.
Patients may view the same mathematical probability differently, depending on how they view the burden.
For example, if a condition is considered clinically mild and has no major effect on day-to-day living, a family may view the 50 per cent chance of passing on this condition differently from a more serious condition inherited in the same way, such as Huntington's disease.
|AUTOSOMAL RECESSIVE INHERITANCE|
This is an example of the inheritance of autosomal recessive conditions, such as cystic fibrosis. The diagram shows the parental chromosomes containing the gene for the condition, and how they 'move' into the eggs and sperm and then into offspring. The usual form of the gene is coloured yellow and the variant form is coloured black.
When a parent who is a carrier makes eggs or sperm (gametes), the usual form of the gene will segregate into half of the gametes, the altered gene into the other half. Each egg or sperm has a one in two chance of containing the usual or the altered gene. There are four possible combinations. At conception, each child of two parents who are carriers has a one in four probability of having two copies of the usual gene, one in two of having one copy of the usual gene and one altered (and so being a healthy carrier) and one in four probability of inheriting two copies of the altered gene and being affected with the condition.
Families with genetic conditions have said they prefer to hear the terms 'chance' or 'probability' rather than 'risk'. Information about probability can be given as odds or a percentage.
How the information is presented may affect an individual's perception of that probability: some people find a figure presented as a proportion more concerning than the equivalent percentage.
Giving the counterbalance of chance also ensures that the individual understands the difference between what he or she perceives as the unwanted and wanted outcomes.
For example, when talking to a couple who are both carriers of sickle cell anaemia, the discussion should include both the chance of a child being affected with the condition (one in four, or 25 per cent) and of a child being unaffected (three in four, or 75 per cent).
It is important to stress that the probability/risk figure is for each individual or pregnancy. For instance, the recurrence risk of 25 per cent for a couple with a child with an autosomal recessive condition applies to each future child. This is important because the couple may believe that if they have already had one affected child, their next three pregnancies will be unaffected.
People can have preconceived ideas about their own risk. This may affect how well they take in new information about the condition in their family.
For example, a female may not believe she is at risk of an autosomal dominant condition such as familial adenomatous polyposis that is present on her father's side of the family as, by chance, only the men in the family have so far been affected.
In addition to using the terms 'chance' or 'probability' rather than 'risk', terms commonly used to describe genetic concepts and conditions can often be seen as emotive. In a study on patients' experiences of receiving genetic information, they said they did not want to hear medical jargon and that healthcare professionals should be mindful of how they use genetic terminology.
For instance, using 'mutation' is seen as unhelpful and hurtful. We recommend health professionals use terminology such as 'alteration' instead of 'mutation', and 'a child with Down's syndrome' rather than 'a Down's syndrome child'.
There are many ways to help patients understand, including using visual tools to explain inheritance patterns, or providing the mathematical probability of recurrence as either odds or a percentage.
When talking about genetics, be mindful of the words you use and how your patient may perceive their meaning, as some genetic terminology may have negative connotations.
- Professor Farndon is a director, and a professor of clinical genetics, and Ms Bishop is an education development officer for the NHS National Genetics Education and Development Centre
- This falls under section 6 of the RCGP curriculum 'Genetics in Primary Care'
1. Use diagrams to explain how genes are passed from parent to child.
2. Carefully choose the right terminology for each patient.
3. Present risk either as a percentage or proportion (one in two) depending on the patient.
1. Burke S, Bennett C, Bedward J, Farndon P.
The experiences and preferences of people receiving genetic information from healthcare professionals. Birmingham: NHS National Genetics Education and Development Centre, 2007.