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The challenge of genetics and consanguinity for General Practice

4 October 2010
By Dr Rizwan Alidina and Dr Mohamed Walji
Balsall Heath Health Centre, Birmingham
Appeared in BioNews 578
A Dispatches programme on rare genetic conditions and cousin marriage aired a few weeks ago ignited much debate. Many people commenting on the programme were correct to say consanguinity alone isn't the issue.

Other factors, such as marriages within small communities and mutations supported by selection pressure could also influence the high prevalence of such rare mutations. However, the high rate of autosomal recessive disorders in some communities remains an important issue, regardless of its intricate and complex causes. This needs to be addressed, preferably with input from general practitioners.

Although autosomal recessive disorders are caused by inheriting a copy of a faulty gene from each parent, the risk of this occurring is higher in communities where consanguinity is common. The prevalence of consanguinity in some ethnic communities is 50-70 percent over several generations, which - in itself - significantly increases risk.

During pregnancy, fetuses are screened for several factors affecting wellbeing, such as maternal age, social deprivation, rubella and nutrition - particularly folate deficiencies to prevent neural tube defects. Each of these has an associated campaign with opportunities for screening or intervention.

But there are no similar campaigns offered for genetic conditions, apart from sickle cell and Thalassaemia screening. In general, there are few interventions designed to reduce autosomal genetic illness by increasing genetic literacy and improving informed reproductive choice. Besides, ten weeks into a pregnancy is not the time to counsel a future parent about their genetic risk.

Counselling should be undertaken early and in a sensitive and non-judgemental manner by healthcare professionals familiar with the patients, their families and their community.

Silent unaffected carriers have the least support. Affected patients and their families are often seen and counselled by various healthcare professionals, including clinical geneticists. But, for each affected patient, there are a multitude of carriers who often don't have the same support to make informed reproductive choices.

We have to concentrate on these patients in primary care and no one is better positioned to help than the carrier's GP who has an intricate understanding of the family and the dynamics of the patient's community.

Practice genetics registers, such as those for chronic diseases, could be useful for identifying families at risk. This would allow referral of families to the local clinical genetics department where they could be cascade tested to identify other carriers. These carriers can be counselled for genetic risk when appropriate, perhaps pre-martially or pre-conceptually.

The time for action is now. GPs need to improve their genetic literacy so they can get involved in discussing the increase in risk seen in those communities where consanguinity is common. They should become more aware of the risks in their communities and familiarise themselves with resources available to them to tackle them.

Discussions about genetic risk must be done in a non-judgemental and non-political manner to ensure attempts to link this issue with religion, culture and politics does not interfere with the delivery of key, but simple, genetic education and the encouragement of informed reproductive choices among at-risk families and communities.

17 September 2012 - by Professor Sandy Raeburn 
This monograph is desperately needed. Western societies, who often chose consanguineous marriage in the past, have grown to fear it and to denigrate communities where it is commonly practiced...
13 December 2010 - by Seil Collins 
A genetic testing service to identify people with Familial Hypercholesterolaemia (FH) is being rolled out across Wales. The service follows two successful FH testing pilots - one in England and one in Wales...
11 October 2010 - by Sarah Pritchard 
A three-year genetics project has been launched in Birmingham to help tackle the city's high infant mortality rate by raising awareness of inherited genetic disorders...
6 September 2010 - by Anshu Rastogi 
'When Cousins Marry' (Dispatches) was a difficult film to make. It was painful at times but immensely rewarding in the end. The film was commissioned because it highlighted a potentially avoidable cause of serious disabilities in hundreds of British children each year...
31 August 2010 - by Professor Sandy Raeburn 
Why am I criticising a campaign to reduce the incidence of severe autosomal recessive diseases? After all, I spent five years of my 40-year clinical career in medical genetics living in Oman - a Muslim country where over 50 per cent of marriages are consanguineous? Let's dig deeper!...
10 May 2010 - by Victoria Kay 
Charles Darwin's concerns that his children's ill health was due to his cousin marriage were justified, according to a new study. The UK-Spanish study, which analysed four generations of Darwin's family, provides statistical evidence of a link between ill health and the degree of inbreeding in his and his wife's families....
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