A diagnosis of Ataxia-Telangiectasia (AT) is normally made on the basis of clinical evidence. The doctor will assess the patient’s symptoms and make a diagnosis on this basis. In doing this, the most important features are the neurological symptoms, particularly progressive cerebellar ataxia and abnormalities in the movements of the eye, together with telangiectasia (spider veins) in the whites of the eyes or other areas of the face and ears. Recurrent infections, due to immunological problems, may or may not be apparent.
Getting a diagnosis of AT can sometimes take a frustratingly long time. Often a child being ‘a bit wobbly’ alerts parents that something is wrong, but there could be many reasons for this. Even when ataxia is diagnosed, it may not be clear that this is progressive. Other more common conditions may be suspected first, (frequently cerebral palsy). It is only when the symptoms get worse, which does not generally occur in cerebral palsy, that another diagnosis is considered.
The fact that AT is such a rare condition, which many doctors are not familiar with, does not help. However, with the establishment of national centres of expertise and the excellent work specialist doctors do in linking with local clinicians, a real difference is being made to improve the situation.
In the UK, all cases of suspected AT are confirmed by submitting a sample of blood for laboratory tests. The initial two main tests carried out are to assess whether there is increased sensitivity of cells to radiation and to look for evidence for loss of the ATM protein.
Once the tests have confirmed this likely diagnosis of AT, the lab will sequence the person’s DNA to identify the two specific mutations the individual is carrying, one received from each parent. This is the ‘gold standard’ for confirmation of the diagnosis.
This process is very important. There are a few mutations which can give rise to a slightly milder form of AT and analysis will show if this is the case. Patients will be given this information when they receive the results of tests. They will also be referred immediately to the appropriate national centre, Nottingham for children and Papworth for adults.
Genetic Testing is now completed by The National Genomic Testing Service, through a Network of 7 Genomic Laboratory Hubs (GLHS) in England. (There will be a different system in Scotland, Wales and N Ireland). The process is started with a referral from your GP, Consultant or Local Genetics Service.
Support around diagnosis
If you have a suspected diagnosis of Ataxia-Telangiectasia (AT) and are waiting for test results, or you are trying to access testing for A-T, please contact our Support Team Kay Atkins (Head of Services) or Anne Murray (Advocacy and Support Manager) on 01582 760733 or email Support for advice.