Embryo Screening Allows To Safeguard Against Alzheimer's Disease In Children

15.08.2012

Couples who fear that their children could inherit a rare form of Alzheimer’s will now be able to screen their embryos to have babies who are free of the disease.

The Government’s fertility regulator, the Human Fertilisation and Embryology Authority (HFEA), has decided to allow fertility clinics to test embryos for two genes that put children at risk of developing the condition as early as 35.

The decision means that any couple with a family history of early-onset Alzheimer’s – up to 5,000 people in the UK – could pay to create a number of embryos at an IVF clinic and have them screened.

Only those found to be free of the genes would be implanted back into the womb. Parents themselves do not need to be tested, or find out if they have the genes.

Although the screening offers couples the chance to have healthy children, there are ethical concerns over the procedure because Alzheimer’s is widely regarded as an illness of age, and not a disability.

Even early-onset Alzheimer’s does not tend to affect most people until they are in middle age.

It is already possible to screen embryos for more than 100 fatal and debilitating conditions, including hereditary breast cancer, cystic fibrosis and muscular dystrophy.

Opponents of the technique –known as pre-implantation genetic diagnosis, or PGD – argue that it offers those who can afford it a way of screening out disability and could lead to parents determining a child’s hair colour, intelligence or even sporting ability.

But neuroscientist Professor John Hardy, of University College London, an expert in the genetic causes of Alzheimer’s, said: ‘I’m so happy the HFEA has done this. It means families will be free of this scourge for all future generations and will really give people some hope.’

The regulator made its decision last month following an application by Guy’s Hospital in London. Minutes from the HFEA’s licence committee read: ‘The Committee noted that there is no cure for this disease and treatment is supportive only. Early-onset Alzheimer’s disease is devastating both for patients and their families.

‘The impact of the condition begins before onset and continues throughout the lives of all of the family members, especially the patient’s children, who will have witnessed the profound deterioration this condition causes.’

The application was supported by the charity Genetic Alliance UK. Spokesman said: ‘We welcome this decision. We’ve found that, in many cases involving conditions developed later in life where whole families have been affected over generations, people choose not to have children at all rather than subject them to the risk of facing the conditions themselves.’

There are about half a million people with Alzheimer’s in the UK. Up to five per cent of cases involve early-onset Alzheimer’s and a small proportion of these – up to 5,000 – will have a genetic cause. The latest application approves testing for two genes – PSEN-1 and PSEN-2 – that are linked to most of the cases.

In 2007, the HFEA approved testing for a third gene, APP, for a specific case. The clinic was given permission to test the embryos of London couple C. and D. because his mother, grandmother and two uncles had died prematurely from the condition.

Dr L. P., of Alzheimer’s Research UK, said screening could give ‘peace of mind’. But she added: ‘The testing could raise some moral issues because, unlike other genetic diseases that can strike at a very young age, people with early-onset inherited Alzheimer’s can still have many decades of their life before symptoms start to show.’

S., 33, said she would not use the tests despite her mother, T., being diagnosed with early-onset Alzheimer’s four years ago at 60. The mother of two from Brighton said: ‘My mum is no longer the person she was – she’s not my mum.

‘But she has had the most incredible life. If someone had discarded her as an embryo, she would not have had the past wonderful 60 years, and that’s heartbreaking.

‘It’s impossible to test for when this disease would start and dementia can come to anyone.’

A spokesman for Hospital said: ‘Each application we make to the HFEA is made on behalf of the individual patients who have been seen and counselled by us. However, once granted, a licence can benefit other couples who may approach us for PGD with the same condition.’

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