The impact of genetic risk on UK Pakistani families 25/11/03. By Alison Shaw How does genetic risk influence reproductive and marital decisions by British Pakistanis, among whom marriage to relatives such as cousins may be preferred? Alison Shaw and Jane Hurst are investigating.

Among British Pakistanis, marriage to relatives such as first cousins may be preferred, as a means of reducing the social risks of marriage outside the family. Yet biomedical research has shown that consanguineous marriage to 'blood relatives' such as first cousins increases the risk of genetic disorders. This presents challenges not only to UK Pakistani couples who are currently having or hoping to have children, but also to doctors who provide genetic services, as Alison Shaw and Jane Hurst are finding out.

Infant mortality and childhood morbidity rates are higher among British Pakistanis than other ethnic groups. The various reasons for this include consanguineous marriage, which increases the risk of recessive genetic disorders. But adverse birth outcomes among British Pakistanis are not always the result of consanguineous marriage, and marrying relatives does not always result in the birth of children with recessive disorders.

Genetic risk

For anyone, the risk of having a child affected by a genetic condition is comparatively low. According to birth incidence data, the risk of having a child with a congenital or genetic (including recessive) disorder is about 2 per cent. The risk doubles to about 4 per cent for first-cousin couples, mainly because of the increased risk of recessive disorders.

(Recessive disorders are associated with inheriting two copies of an identical mutation; cousins are more likely to inherit an identical mutation because of sharing a pair of grandparents, one of whom might carry a mutation that they could pass on to their children and grandchildren.)

Background: Recessive diseases

There is a further approximately 2 per cent risk for first-cousin couples where there is also a history of consanguineous marriage in the family. Even so, a cousin couple is far more likely to have a child unaffected by recessive disease than to have an affected child.

The identification of a recessive disorder in a child has reproductive implications for the parents, who, as unaffected carriers each carrying a single copy of the mutation, have a one in four risk of having further affected children. It also has particular genetic implications for families in which consanguineous marriage is preferred, as it raises the possibility that other members of the families are unaffected carriers, who risk having affected children themselves if marriages have taken place or are planned between them.

A new study

The problem that faces clinicians is how to deliver genetic services without stigmatising British Pakistanis on the basis of their marriage pattern. Very little is known about the social impact of genetic risk information on reproductive decision making and processes of marriage arrangement. With funding from a Wellcome Trust Biomedical Ethics grant, Dr Shaw, a social anthropologist at Brunel University, and Dr Hurst, a consultant clinical geneticist at the Churchill Hospital, Oxford, aim to find out.

In most of the British Pakistani families in this study, a child has been referred to the genetics services for diagnosis. By August 2003, 37 families had been recruited to the study and 36 cases of genetic or probably genetic disorder had been identified: 27 'recessive' or 'probably recessive' disorders, four dominantly inherited conditions, and five chromosomal rearrangements or mosaicism. Of the 37 sets of parents, 33 are consanguineous. The families in the study are being followed through their experiences of referral to clinical genetics services.

The research has already offered insights into how clinical information is being communicated and understood, and into the problems of communicating this information, especially where clients do not have English as their first language or lack prior understanding of what distinguishes genetics from other medical services. At times, Dr Shaw, who speaks Urdu, has the role of interpreter and mediator, thus assisting the clinical processes that she is observing while enabling her own research.

Genes, risk and the family

The research has found that, for many UK Pakistanis, the very idea of 'genetic' disease is unfamiliar, and competes with social, environmental and spiritual understandings of the causes of illness. It has also found that families understand probabilistic risk information not in abstract terms, but according to the social context and circumstances of their lives. Where a recessive disorder is diagnosed, the one in four recurrence risk is interpreted in very different ways by different couples. Their interpretations reflect their prior experiences of fertility and disability, the expectations and experiences of other family members such as siblings and senior kin, their marital and family circumstances, and the social environment of contemporary Britain.

Social considerations and religious beliefs also influence the ways in which individuals and couples negotiate the practical ethical issues associated with prenatal diagnosis. A desire for scientific knowledge and good medical care coexists with considerable ambivalence about the use of modern medical technology, especially with respect to termination of pregnancy.

The research also shows that genetic risk information is not necessarily communicated easily or readily with other members of the family. Some couples who have suffered the death of an infant or who are preoccupied with caring for babies or children affected with recessive genetic disorders do not wish to discuss their own carrier status and recurrence risk with other family members, for this is a painful and private matter. Some such couples do not realise that their unaffected siblings or children may also be carriers, while others who try to discuss genetic risk with other members of the family may be greeted with scepticism.

Couples with affected children may also consider it would be wrong for them to worry any brothers or sisters married to cousins who have no affected children, or have completed their families, particularly where carrier or prenatal tests are not available for the disorder in question. In this group of patients, the recessive disorders are in most cases extremely rare, and carrier and antenatal genetic tests are available for only a small proportion of the disorders diagnosed.

Most of the unaffected children of couples in this study are too young to be married, so it is too early to know to what extent parents will take account of their children's carrier or possible carrier status when, or if, they come to arrange their children's marriages. One young woman whose siblings have a severe recessive condition was married to a relative more distant than a first cousin, significantly reducing the risk of shared mutations in the absence of carrier tests. On the other hand, some parents emphasise that a person with a mild disability is likely to be better cared for if they are married within the family than if they are married outside.

Some couples were afraid to attend the genetic clinics for fear that they would be 'blamed' for being married to cousins. This reflects the negative public and biomedical discourse on genetic risk and cousin marriages. An undue emphasis on the genetic risks of marrying within the family can be devastating to couples in need of support when considering their reproductive options, or who are caring for a child or children with medical problems.

Genetic information and its implications for reproductive decision-making and for other family members needs to be explained clearly and sensitively through a close relationship built between genetics clinic doctors and their clients.

Dr Alison Shaw is at the Department of Human Sciences at Brunel University. Dr Jane Hurst is at the Department of Clinical Genetics at the Churchill Hospital, Oxford.

Image credit: Anthea Sieveking

Further reading

Bundey S and Alam H. A Five-Year Prospective Study of the Health of Children in Different Ethnic Groups, with Particular Reference to the Effect of Inbreeding. European Journal of Human Genetics 1993 1: 206-219. Abstract

Shaw A (2003) Genetic counseling for Pakistani and Bangladeshi origin Muslim families in Britain. The Encyclopedia of the Human Genome, Nature Publishing Group.

Shaw A. Attitudes to genetic diagnosis and the use of medical technologies in pregnancy (forthcoming), Chapter 1 of Maya Unnithan-Kumar (ed), Reproductive Agency, Medicine and the State: Cultural Transformations in Childbearing, (Oxford, Berghahn Books).