Once seen as one of the last frontiers of medicine, genetic testing for congenital and adult-onset inherited diseases has taken great strides in recent years. Yet, genetic testing and counselling remains a very stressful and complex experience for families.
Meeting with consultant clinical geneticists, Prof Andrew Green and Dr Lisa Bradley, and genetic counsellors, Tara Clark and Karen Pierpoint, at the Department of Clinical Genetics at Children’s Hospital Ireland (CHI) at Crumlin, it’s easy to imagine how daunting it must be for families arriving to find out whether their child has a congenital genetic disorder or whether they or their family members are at risk of an adult-onset inherited condition, such as Huntington’s disease.
“Finding out at the right time is crucial because once you have genetic results, you can’t unknow them,” explains Pierpoint. She says that people need to be at their best mental health before embarking on genetic testing. “They need to be supported to be in the best position to deal with bad news – or even good news, which can leave some people feeling guilty about not having a condition,” she explains.
Couples seeking genetic testing during pregnancy are offered genetic counselling, with genetic counsellors working in conjunction with the clinical genetic consultants. However, adults seeking predictive testing for neurodegenerative conditions, such as Huntington’s Disease are given a minimum of two appointments with a genetic counsellor with an appointment with a psychiatrist scheduled in between these two appointments.
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Pierpoint adds that while individuals can be tested for an inherited neuro-degenerative condition, such as Huntington’s, from the age of 18, many decide not to come forward for testing.
Prof Green explains that there is a genetic explanation for between 20 and 30 per cent of children with conditions who are brought in for genetic testing. “There are hundreds of different causes of intellectual disability and each condition can be very rare, yet 80 per cent of all rare diseases are genetic, involving about 6 per cent of the population.”
The couples who would have travelled to the UK for a termination before the laws were changed in Ireland, still do
— Tara Clark, genetic counsellor
In Ireland, there isn’t publicly funded screening during pregnancy for known chromosomal abnormalities which result in Down syndrome, Edwards syndrome and Patau syndrome. “In countries such as Netherlands and Denmark, all pregnant women are tested for these chromosomal syndromes and, in the UK, pregnant women are tested if there is a risk, such as age,” explains Prof Green, who is professor of medical genetics at University College Dublin.
But with other conditions such as cystic fibrosis (CF), great advances have been made, with newborn screening in place since 2011. Ireland has the highest number of carriers of cystic fibrosis in the world, with a one in 19 chance of being a carrier of CF. When a newborn baby is diagnosed with CF, the family is referred to the Department of Clinical Genetics, where Clark will see them within six to nine months. “We see these families because of the implications for wider family members [and] the siblings of the parents, and if they have more children as well as when the child with CF is older,” explains Clark.
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The current Irish legislation on abortion (which permits the procedure for up to 12 weeks of pregnancy except in cases of fatal foetal abnormalities) has not changed the options for most pregnant women who have genetic results identifying abnormalities in the foetus.
“The couples who would have travelled to the UK for a termination before the laws were changed in Ireland, still do,” says Clark. This is because the standard genetic test, chorionic villus sampling (CVS), is usually carried out 11 weeks into the pregnancy and the results don’t come back for over a week – leaving it too late for couples to have an abortion in Ireland unless there is a fatal foetal abnormality. Genetic counsellors do, however, meet couples before the results come back to discuss their options.
While genetic testing has improved hugely in recent years, the practice of non-specialists sending genetics tests to a variety of laboratories around the world is a concern for the consultant clinical geneticists at CHI at Crumlin. “Testing has improved,” explains Dr Bradley. “In the past, we were more like detectives testing for one thing we knew about. Now, we look at hundreds of genes on genetic panels and do whole exome analysis [a single test that can detect many genetic disorders], which allows us to discover more subtle forms of different conditions.”
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However, as genetic testing becomes more mainstream, consultants – who are not genetic specialists – can request genetic tests at laboratories throughout the world, some of which the consultant clinical geneticists at CHI at Crumlin wouldn’t always vouch for. “We currently don’t have a centralised laboratory dealing with all testing, and any clinician can order genetics tests from anywhere in the world,” says Dr Bradley. “It may go to a lab that we hesitate to send it to or it may not even be the correct test that goes. It may be interpreted wrongly or even [be] a duplicate of a test already carried out.”
I tell people, ‘You are the expert in the condition. Don’t expect medical staff to know. You will be educating them about it’
— Dr Lisa Bradley
This potentially disastrous scenario could result in inaccurate test results or, without expert knowledge, test results which could be misinterpreted. Both Prof Green and Dr Bradley stress that expertise in peri-natal genetics is a priority of the National Women’s Health Action Plan. “As genetic testing becomes more mainstream, with primary consultants doing the testing, we need more expertise to interpret these results. For example, a genetic test might signal a risk of another cancer later in life which medicines might be already available to prevent,” explains Dr Bradley, who specialises in the genetics of cancer.
The lack of electronic recording of genetic tests carried out is another concern for the consultant clinical geneticists and genetic counsellors at the Department of Clinical Genetics. All nod eagerly when asked whether electronic health records could improve genetic services for families in Ireland. Such a digital record would also prevent unnecessary duplication of tests.
Currently, what happens is that families who have a child with development delay or birth defects – who are keen to understand the genetic origins before having more children or to inform other family members of the risk of the condition – carry a letter from their genetic consultant to subsequent appointments with medical personnel. There is no electronic information stored for other medical professionals to access before seeing new families who have a child with a rare congenital or inherited disorder.
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“I tell people, ‘You are the expert in the condition. Don’t expect medical staff to know. You will be educating them about it,’” says Dr Bradley. Families do, however, have access to specialists and patient groups in rare diseases throughout Europe as part of the European Commission-funded European Reference Networks for rare diseases. The National Centre for Clinical Genetics in Dublin, which is a member of the network on rare malformation syndromes and rare intellectual and neuro-developmental disorders (ERN-ITHACA) and the network on rare inherited heart conditions (ERN GUARD-Heart), runs specialist clinics in these areas.
