Genetic testing
Huntington’s predictive testing
The structured, counselled pathway for learning whether you carry the Huntington’s disease gene before symptoms appear.
Key facts
At a glance
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The choice is the point: at 50% risk, testing is a personal decision - international protocols protect the right not to know as firmly as the right to know.
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The process: a structured series of counselling sessions over weeks before any blood is drawn, with a companion encouraged throughout.
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The result: repeat length in the HTT gene gives an essentially definitive answer - it does not, however, predict age of onset precisely.
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Alternatives: family planning options, including PGT-M and non-disclosure testing, exist without learning your own status.
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Insurance note: uniquely in the UK, insurers may ask about a predictive Huntington’s test result only for life cover above £500,000 - counselling covers this precisely.
The full picture
What this test involves, and how to get it
Predictive testing for Huntington’s disease answers, with near certainty, whether a person at 50% risk will develop the condition - which is exactly why the pathway is deliberately slow. International protocols, followed by UK genetics services, structure the process as a series of counselling sessions across weeks: exploring motivations, imagining both results, planning support, and preserving at every stage the freedom to stop - many people enter the pathway and choose not to proceed, a choice regarded as fully valid. The blood test itself measures the CAG repeat length in the HTT gene; results are given in person, with follow-up built in. The number confirms or excludes the mutation but does not precisely date onset, an honest limit discussed beforehand.
Around the decision sit alternatives counselling will map: prenatal and pre-implantation (PGT-M) options exist that protect children without revealing a parent’s own status, using non-disclosure designs. On insurance, Huntington’s occupies a unique position in the UK Code on Genetic Testing and Insurance: it is the single condition for which insurers may ask about a predictive test result, and only for life insurance above £500,000 - below that threshold, and for other policy types at standard levels, predictive results are not requested. A favourable existing result may be volunteered if it helps you. NHS predictive testing through regional genetics centres is the standard route and is well run; private genetics services offer the same protocol-led process with shorter routes in, but the counselling structure - not speed - is the feature to protect.
A quiet reminder
This guide is for information, not medical advice.
Your own clinician knows your history and can tell you which parts apply to you. Next review of this page: 2027-09-27.
Frequently asked
Common questions about Huntington’s predictive testing.
Quick, plain-English answers to what people ask us most.
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What is Huntington's predictive testing?
This is a genetic blood test that checks for the specific gene mutation that causes Huntington's disease, an inherited condition affecting movement, thinking, and behaviour, usually offered to people who have a parent or close relative diagnosed with the condition but do not yet have symptoms themselves.
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Why would someone consider this test?
People at known risk, typically because a parent has Huntington's disease, may consider predictive testing to find out whether they carry the gene, which can inform family planning, life decisions, and future healthcare planning, though the decision to test is deeply personal.
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Do I need to prepare for Huntington's predictive testing?
Yes, this test is never done as a simple standalone blood draw; it is preceded by structured pre-test genetic counselling, usually over several sessions, to make sure you understand the implications and are supported in your decision, given the profound and irreversible nature of the result.
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What happens during the testing process?
After genetic counselling, a blood sample is taken and sent for specialist genetic analysis. Results are given in person, again with counselling support, rather than simply by letter or phone, given how significant the information can be.
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How long does the process take?
The overall process, including pre-test counselling, testing, and results delivery, often spans several weeks to a few months, reflecting the careful, staged approach used for this type of predictive genetic testing.
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What does a positive result mean, and what happens next?
A positive result means you carry the gene mutation and will develop Huntington's disease at some point, though it cannot precisely predict when symptoms will start or how they will progress. Ongoing support from genetic counsellors and specialist services is provided to help with the emotional and practical implications, and this should always be discussed in detail with the specialist team supporting you.
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Is Huntington's predictive testing accurate?
The genetic test itself is highly accurate at detecting the specific mutation. The complexity lies not in the test's accuracy but in the profound personal, family, and psychological implications of the result, which is why counselling is central to the process.
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How much does this cost, and is it available on the NHS?
Huntington's predictive testing is available on the NHS through specialist clinical genetics services, usually the recommended route given the counselling support required. Cost varies by provider for those seeking a private genetics pathway, though this area is typically best accessed through specialist NHS or dedicated genetic counselling services.
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How do I access Huntington's predictive testing?
This is arranged through referral to a clinical genetics service, which will guide you through pre-test counselling before any decision to proceed with testing is made.
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Can I change my mind during the process?
Yes, you can stop the process at any stage before receiving your result. The counselling process is specifically designed to support your decision-making without pressure to continue.