How did I get ADPKD
ADPKD occurs when mutations in certain genes cause them to function abnormally.
In ADPKD, two genes are known to be involved: PKD1 and PKD2. These are located on chromosome 16 and chromosome 4 respectively of the 23 chromosomes that are found in the cells of every human. Chromosomes exist in pairs and in ADPKD one abnormal, or mutated, copy of the pair is inherited, usually from one affected parent - who can either be the mother or the father. Each time a child is conceived, there is a 1 in 2 chance of that child inheriting the mutated gene.
The majority of people who inherit ADPKD (approximately 85%) will have a mutation in the PKD1 gene, with the remainder (approximately 15%) having a mutation in the PKD2 gene. PKD1 mutations are associated with an earlier onset of kidney failure, which occurs at an average age of around 55 years.
Very rarely a spontaneous alteration in the genetic information may occur and in these cases neither parent has cysts since they do not carry the abnormal gene. Such alterations, called "new mutations", are uncommon.
Is genetic testing available or useful for me?
Genetic, or molecular, testing is of great interest to people with ADPKD. The test checks blood DNA for an abnormality that may indicate a predisposition to a disorder, or confirms a suspected mutation. In ADPKD, a gene change must be found before testing family members, otherwise predictive testing is not possible.
If you have ADPKD symptoms, however, a genetic or molecular test is not usually necessary. ADPKD is typically diagnosed by a scan (ultrasound, CT or MRI). The number of cysts, if any, together with your family history, will be sufficient to confirm whether you have ADPKD or not. Find out more about how ADPKD is diagnosed.
It is important to bear in mind that, while a scan or a molecular test may confirm that you have ADPKD, it will not tell you when problems will begin or how severe, the range of symptoms, or how quickly your kidneys may deteriorate.
While that PKD1 is usually more severe than PKD2, there is very wide variation in the severity of the disease overall.
Knowing which gene change you inherited will not help you manage the condition better. In fact, there may be negative consequences. You must disclose a diagnosis when applying for insurance or if declaring medical conditions.
Should my children be tested?
Generally, testing children for ADPKD is not advised unless they show symptoms. Presymptomatic diagnoses remove a child’s right to choose and may cause them distress growing up.
On rare occasions, parents request a gene test on a foetus. If there is no known gene change in the family this may not be possible to do. However, where there is a significant risk to the unborn child, genetic testing along with counselling, should be investigated. ADPKD is licensed for PGD (pre-implantation genetic diagnosis) but funding for this procedure is not guaranteed.
Similarly, if a relative of someone with ADPKD is considering donating a kidney and scans are not conclusive, a genetic test may help the donor decide.
Genetic testing and counselling services
If you have a family history of ADPKD, you have a right to access genetic services through the NHS. A GP, paediatrician or renal consultant can refer you to a clinic for information and support from a specialist doctor, usually a clinical geneticist.
You may receive a questionnaire about your family history before your appointment to help the geneticist calculate your risk factors. When you meet, the geneticist will discuss your concerns and draw a family tree. You may also need a clinical examination. These services are specialised and are not available at every hospital, but there are 22 genetics centres in the UK so there is no need for anyone to be denied access.
UK Genetics Centres: www.bshg.org.uk
Learn more about genetics
The information on this page is under review by the PKD Charity using the accredited Information Standard process.
PKD Charity Helpline: The PKD Charity Helpline offers confidential support and information to anyone affected by PKD, including family, friends, carers, newly diagnosed or those who have lived with the condition for many years.
Disclaimer: This information is primarily for people in the UK. We have made every effort to ensure that the information we provide is correct and up to date. However, it is not a substitute for professional medical advice or a medical examination. We do not promote or recommend any treatment. We do not accept liability for any errors or omissions. Medical information, the law and government regulations change rapidly, so always consult your GP, pharmacist or other medical professional if you have any concerns or before starting any new treatment.
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