This article appears in the following InnovAiT issue: Special issue; Genetics in primary care [View the issue table of contents]
Taking and recording a genetic family history
Consultant Clinical Geneticist, Director, NHS National Genetics Education and Development Centre
E-mail: peter.farndon{at}geneticseducation.nhs.uk
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Abstract |
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 TOP Abstract How this topic fits...Box 1. Taking and...The benefits of taking...How should the medical...The extent of family...How to ask for...ResourcesAnswer to the self-assessment...References |
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During a consultation, John remarked:
‘My grandfather and an aunt and uncle died of bowel cancer’.
General practitioners are constantly receiving and documenting such information about family members, but how best can it be recorded and interpreted to decide if an individual is at risk for a genetic disorder?
One of the factors influencing whether John is at an increased risk above that of the general population is whether there is an increased genetic predisposition in the family. The genetic relationships of the affected people and the ages and sites at which the cancer occurred may give vital information for diagnosis and surveillance and risk estimation for John. Did the cancer occur in his paternal or maternal grandfather? Were the aunt and uncle siblings?
This information can be appreciated quickly and easily if it is presented in the form of a medical family history, usually recorded as a family tree which allows a pictorial representation of family relationships and those family members affected by medical conditions. In clinical management, information from the family tree can be just as important as information from a laboratory test. As well as identifying genetic conditions, taking a family history may also provide information about a shared environment, life-style choices, occupations and family interactions. Some National Institute for Health and Clinical Excellence national guidelines include the taking of a family history to inform management, for instance, in cardiovascular disease and certain forms of cancer.
For some conditions, there may be no doubt about the genetic basis. For instance, if a diagnosis of cystic fibrosis is confirmed, then the underlying basis is known: a single gene disorder inherited in an autosomal recessive manner. However, the probability of a family member being a carrier for cystic fibrosis depends on her or his genetic relationship to the affected person. Again, drawing a family history can make the degree of relationship clear, informing the decision as to whether carrier testing is indicated.
Taking and recording a family history is recognized in GP curriculum statement 6 (Genetics in Primary Care) as being a key skill in identifying ‘those patients in the practice population with, or at risk of, a genetic condition’ (Box 1). The taking and recording of the family history should of course not be an end in itself. As well as emphasizing the importance of knowing the relevant questions to ask, the curriculum statement also highlights that to be able to interpret the pedigree pattern, an understanding of the genetic basis of the common patterns of inheritance is vital. This article concentrates on taking and recording the family history. Being able to recognize the family pedigree patterns of the different modes of inheritance and the core genetics concepts, which underpin them, are discussed in the accompanying articles.
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Primary care management
Knowledge and skills
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The benefits of taking and recording a genetic family history |
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TOPAbstractHow this topic fits...Box 1. Taking and...The benefits of taking...How should the medical...The extent of family...How to ask for...ResourcesAnswer to the self-assessment...References |
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The three main reasons in primary care for gathering information about the family history are shown in Box 2. There are several other benefits that are discussed below.
Box 2. Three main reasons for collecting genetic family history information in Primary Care
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The genetic family history can reveal patterns of inheritance which may help in refining a diagnosis
Recognizing a pattern of people with a particular condition may suggest an underlying genetic mechanism (as discussed in the next article). The pattern may also help to distinguish between conditions with similar presentations because they are known to have different modes of inheritance.
When taken together, similar or related symptoms occurring in several members of a family may suggest a unifying diagnosis. This is particularly important for some autosomal dominant disorders which have variable expression (such as neurofibromatosis type 1 or forms of osteogenesis imperfecta).
The genetic family history is used to assess the likelihood of genetic disease occurring in relatives and so can affect testing, treatment and management strategies
The closeness of the biological relationship between a family member and a person with a genetic condition can be clearly seen in a family pedigree, and if the mode of inheritance of the condition is known, the probability of his or her having inherited the gene for the condition and so being affected or a carrier can be determined. Guidelines for investigation, management and surveillance (for instance, colonoscopy or mutation analysis for inherited bowel cancer) can thus be instituted for other family members who may have been identified to be at risk.
The genetic family history can highlight the need for referral for specialist opinion
Where someone has been identified as being at higher risk as a result of their family history, it may be appropriate to refer the patient for specialist opinion (such as a suspected diagnosis of Marfan syndrome). Details about the pattern of disease and affected members will be valuable information for genetic and other specialists.
Taking the genetic family history helps to build rapport with a patient and to explore his or her understanding
In addition to having medical benefits, eliciting genetic family history information creates opportunities for the patient and history taker to develop trust, to ask questions and to correct any misconceptions about a symptom or illness.
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How should the medical family history be recorded? |
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Family history information is usually collected during a clinical consultation and used to draw a family tree in the presence of the person giving the information. There is international agreement that standardized pedigree symbols should be used to ensure that health professionals throughout the world can share, understand and interpret family history information. It is therefore useful for medical practitioners to be able to ‘read’ a pedigree, even if their roles do not include taking family histories regularly.
There are other ways of collecting family history information; for instance, the patient or family may agree to complete a family history form, where details of each family member in turn are entered in a table (e.g. please give the name, date of birth, appropriate medical information about yourself, your own children, your sisters [full and half] then brothers, your mother and father, your mother's mother and father ... and so on). This table of information could then be incorporated into the medical record, but it may be more difficult to appreciate biological relationships and a potential pattern of inheritance from linearly arranged information. Most clinicians therefore prefer to see family history information represented in a pedigree. Cancer genetic services often collect family history information through a form, but usually convert it to pictorial form by drawing a pedigree.
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The extent of family information to be gathered |
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How much information should be collected? Genetics services take a detailed family history usually of three generations and record information about all medical conditions in the family. This may also be appropriate when a family joins a general practice to gain a full picture and may highlight an increased incidence of conditions such as diabetes or hypertension which may warrant the family being flagged for surveillance and their being warned to report symptoms.
However, collecting information on everyone in a very large family may prove to be too time-consuming during routine consultations in primary care. Although three generations may be considered standard, it may be appropriate to ask about only two generations or more than four depending on the genetic basis of the condition being considered and the size of the family. Perhaps the minimum is to aim to gather enough information on first-degree relatives (children, sibs and parents) of an individual, supplemented when appropriate by information about other relatives to inform a preliminary assessment of genetic risk.
Indeed, an even more targeted approach may be justified in some clinical situations—for instance, to check for a family history of a particular condition rather than a general enquiry. In a family with cystic fibrosis or Down syndrome, it is likely that the family will be asking specifically about recurrence risks for these conditions.
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How to ask for information and draw the pedigree |
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The internationally agreed symbols for drawing a pedigree are shown in the context of a four-generation family in Fig. 1.
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There are commercially available software programs for drawing pedigrees, but most people in a clinical situation draw the pedigree on paper. Whichever method is used, it should be able to record information clearly and accurately. The family tree can be scanned and attached to an electronic medical record.
Here are some questions to ask and guidelines for drawing the pedigree. The process is illustrated in figure 2.
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While asking questions about affected family members, one should be sensitive to the possibility that some people may feel guilty that they have ‘passed on’ the altered gene for a serious condition to another family member. Most families seem content with wanting to ensure that medical histories are shared, but some older family members may associate genetic conditions with a feeling of family shame.
- Depending on the position in the family of the person giving the information—for example, grandparent, parent or child—start on an appropriate area of the page (top, middle or bottom, respectively!) bearing in mind that you may need to record three generations of family members.
- Use clear symbols (circles for females and squares for males). Fill in the symbol if the person is known or reported to be affected with the medical condition about which your patient is enquiring. For a partnership, the usual convention is to place the male partner on the left if possible.
- Record names (check the spelling with the person giving the information), maiden names and dates of birth (rather than ages whenever possible). Give the year of birth if possible if the full date of birth is not known.
- Build up the tree from the ‘bottom’ starting with the person giving the information, or with their affected child and the child's siblings. ‘How many children have you had? Please give me the names of your children, and their dates of birth in order of their ages, starting with the eldest first’. (The usual convention is to place siblings in birth order with the firstborn on the left.) Be careful to distinguish full siblings from half-siblings. You might ask, ‘Are all of your children with the same partner?’ and ‘Are your brothers and sisters from the same parents?’
- As well as asking about children, ask about miscarriages, stillbirths or deaths in each partnership: ‘How many children have you had? Have you lost any children? Have you had any previous partners?’ Being asked about pregnancy losses, stillbirths or childhood deaths can be upsetting for some people. It is often best to be open in your questions (i.e. ‘Did you lose any children? Were there any other pregnancies or pregnancy losses?’) and be sensitive to the feelings of the patient (‘I am sorry to hear of your loss’ if it occurred recently). If a pregnancy was terminated (rather than lost spontaneously), it is important to ascertain if there was a medical reason.
- Next ask about the informant's siblings and his or her children, and then parents, moving from generation to generation as you work up the page.
- If the person has died put a sloping line through the symbol (from the bottom left-hand to the top right-hand corners). If appropriate, record the cause of death and age at death.
- Complete one side of the family before adding information on the other (usually paternal) side of the family to avoid confusion.
- Include affected and unaffected individuals on both sides of the family. The number of unaffected individuals can have an important bearing on risk assessment. Rather than recording full details (names, dates of birth), in the interests of brevity (and sometimes confidentiality), it may be appropriate to draw circles or squares without additional details for people on the periphery of a pedigree. Where there are multiple unaffected people in a sibship, a number can be placed in a circle or square to signify the number of unaffected females or males there are in the sibship.
- Information on parental occupations, past medical and drug history, pregnancy and birth history should be noted, especially where a child has a dysmorphic syndrome.
- Be sensitive when trying to determine if partners are related by blood (a consanguineous relationship). Questions may include: ‘Are you and your partner related?’ or ‘Are there any surnames or maiden names in common in the family?’
- For some genetic conditions it is becoming increasingly important is to ask about population ancestry—‘Originally, where did each of your grandparents come from?’ This may be helpful in determining for which particular DNA variants to test–specific gene alterations associated with cystic fibrosis and thalassaemia, for example, are more common in certain populations.
- Record at least basic details on both sides of the family, even if it appears that a disorder is segregating on one side.
- Date and write your name legibly on the pedigree together with an explanation of any abbreviations. Finally, always ensure that you have asked for permission to share family history information with colleagues and/or other family members and note this.
As you are taking the family history, consider whether a pattern of affected people is unfolding, and if so, is it compatible with one of the Mendelian modes of inheritance described in the article "Recognising the common patterns of inheritance in families" in this issue.
| Pedigree drawing in practice: self-assessment exercise This exercise is offered as an opportunity to become familiar with some of the pedigree symbols and use them in drawing a medical family history.
Can we have a pregnancy test for cystic fibrosis?
You decide that you need to know how Jane is related to Richard, so you ask for more information from Jane Jane has a brother, John Whitehead, who is aged 34 and is well. Their father, George Whitehead, died at the age of 66 from a heart attack, but their mother, Joan, is alive and well at the age of 64. In John Whitehead's first marriage, to Alice (she is now aged 33), they had a son David who is aged 10. He has no medical problems. His second marriage is to Christine (who is 29). She knows no details of her parents and family. Christine had a spontaneous abortion at 9 weeks before Richard, who is aged 4, and has cystic fibrosis. No couples in the family are blood relations.
Use the information that Jane has given you to draw out the pedigree to show all the people mentioned
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Resources |
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TOPAbstractHow this topic fits...Box 1. Taking and...The benefits of taking...How should the medical...The extent of family...How to ask for...ResourcesAnswer to the self-assessment...References |
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Video clips of family histories being taken and recorded are available on the NHS National Genetics Education and Development website www.geneticseducation.nhs.uk.
A small plastic template with cut out symbols and guidelines (Figure 3) for recording a medical family history is available (while stocks last) by mailing your name and address to enquiries{at}geneticseducation.nhs.uk
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Key points
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Answer to the self-assessment exercise: Jane Hobson's family history |
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TOPAbstractHow this topic fits...Box 1. Taking and...The benefits of taking...How should the medical...The extent of family...How to ask for...ResourcesAnswer to the self-assessment...References |
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Figure 4 shows how Jane is related to Richard who has cystic fibrosis.
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As cystic fibrosis is an autosomal recessive condition, where an affected person must have inherited two copies of the altered gene, both John Whitehead and Christine must be carriers. This means that John must have inherited his altered gene from either his mother or father, so one of them must be a carrier. Whichever of Jane's parents is a carrier could pass on either the altered or the normal gene, so Jane has a one in two chance of being a carrier of the altered gene which we know her brother John must have. It is therefore appropriate to offer her genetic testing for the alteration in the gene known to be associated with cystic fibrosis in her family. Whether the baby in her first pregnancy is at risk of having cystic fibrosis depends on whether her husband Christopher Hobson is a carrier.
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References |
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TOPAbstractHow this topic fits...Box 1. Taking and...The benefits of taking...How should the medical...The extent of family...How to ask for...ResourcesAnswer to the self-assessment...References |
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Bennett RL. The practical guide to the genetic family history (1999) New York: Wiley-Liss. ISBN 0 471 25154 2.
Bennett RL, Steinhaus KA, Uhrich SB, et al. Recommendations for standardized human pedigree nomenclature. American Journal of Human Genetics (1995) 56:745–52.[Web of Science][Medline]
Consent and confidentiality in genetic practice: guidance on genetic testing and sharing genetic information. In: Report of the Joint Committee on Medical Genetics (2005) London: RCP, RCPath, BSHG.
Quereshi N, Bethea J, Modell B, et al. Collecting genetic information in primary care: evaluating a new family history tool. Family Practice (2005) 22:663–9.
Rich EC, Burke W, Heaton CJ, et al. Reconsidering the family history in primary care. Journal of General Internal Medicine (2004) 19:273–80.[CrossRef][Web of Science][Medline]
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