Huntington's disease (HD) is an inherited, progressive brain disorder caused by an expanded repeat in the huntingtin (HTT) gene. It gradually affects movement, thinking and behaviour, usually beginning between the ages of 30 and 50, with a juvenile form in about 1 in 20 cases.
Each child of an affected parent has a 1 in 2 chance of inheriting the gene. No treatment yet slows or stops the disease, though research is active. Good symptom control and well organised multidisciplinary support make a considerable difference to daily life.
Symptoms
- Involuntary, dance-like movements (chorea) of the face, limbs and trunk
- Clumsiness, unsteady balance and falls
- Irritability, apathy, depression or anxiety, often years before movement changes
- Difficulty planning, organising, multitasking and concentrating
- Obsessive or impulsive behaviour; limited awareness of one's own symptoms
- Slurred speech and difficulty swallowing
- Weight loss despite eating well
- Later: stiffness, slowness and abnormal postures replacing chorea
- Juvenile form: stiffness, decline at school and seizures more than chorea
Causes and risk factors
HD is caused by an expanded CAG repeat in the HTT gene on chromosome 4, inherited in an autosomal dominant manner. A count of 40 or more always causes the disease if the person lives long enough; 36 to 39 repeats may or may not; 27 to 35 does not cause disease but can expand in the next generation, especially when inherited through the father. Longer repeats usually mean earlier onset. The abnormal huntingtin protein damages neurons, particularly in the striatum. A new mutation with no family history accounts for a small minority.
How it is diagnosed
- Neurological and psychiatric assessment: Motor signs with a compatible family history suggest the diagnosis; the Unified HD Rating Scale follows change over time.
- Diagnostic genetic test: A blood test counting CAG repeats confirms HD in a person with symptoms.
- Predictive testing: For adults at risk who have no symptoms. It follows an international protocol with genetic counselling before and after, time to reflect, and the right not to know. Children without symptoms are not tested.
- MRI: May show shrinkage of the caudate nucleus; mainly used to exclude other causes.
- Tests for HD look-alikes: When the gene test is negative: other genetic choreas, lupus, thyroid disease and medication effects.
- Reproductive genetic options: Prenatal testing and pre-implantation genetic testing with IVF, including methods that avoid revealing the at-risk parent's own status.
Treatment options
- Treatment of chorea: Tetrabenazine, deutetrabenazine or valbenazine reduce movements, with monitoring for low mood; certain antipsychotics are an alternative. Chorea that is not troublesome does not need treating.
- Psychiatric care: SSRIs for depression, anxiety and obsessive symptoms; mood stabilisers or antipsychotics for severe irritability. Suicide risk is raised and should be asked about openly.
- Physiotherapy and exercise: Maintains balance, fitness and mobility, and teaches falls prevention.
- Speech, swallowing and nutrition support: Texture modification, a high calorie diet, and later a discussion about gastrostomy.
- Occupational therapy and social support: Home adaptations, routines to work around planning difficulties, driving and employment advice, and support for carers.
- Advance care planning: Discussed early, while the person can express their wishes clearly.
- Clinical trials: Huntingtin-lowering approaches such as antisense drugs, gene therapy and splicing modifiers are being studied; results to date are mixed and none is licensed. The Enroll-HD registry links families to research.
When it is urgent
Seek urgent local help for suicidal thoughts or plans, severe aggression or psychosis, choking or a chest infection after swallowing difficulty, a serious fall, or a sudden decline, which may be due to infection, medication side effects or a subdural haematoma after a fall.
Travelling to Türkiye for treatment
HD needs continuous, locally coordinated care over many years, and no clinic abroad can alter its course. Treatments sold as cures, including stem cells, are unproven. A visit may help with confirmatory genetic testing and a specialist review of medication, or with IVF using pre-implantation genetic testing for couples who wish to avoid passing on the gene, which requires a laboratory work-up beforehand and about 3 weeks in Istanbul for the cycle. Predictive testing should not be done in a hurry on a short trip without proper counselling and support at home.
Send your reports, scans and a short history and a Clinic-Y coordinator replies within 24 hours with suitable teams and written, all-inclusive proposals side by side. Reviewing your case is free.
Frequently Asked Questions
Should I have the predictive test?
It is a personal decision, and many people at risk choose not to know. Counselling explores the implications for insurance, relationships, family planning and mental health beforehand.
Can it skip a generation?
No. If you have not inherited the expanded gene you cannot pass it on. It may seem to skip when a parent died before symptoms appeared.
Is there a treatment that slows HD?
Not yet. Several gene-targeted approaches are in trials. Be sceptical of any clinic claiming otherwise.
Can we have children without passing it on?
Yes. Pre-implantation genetic testing with IVF or prenatal testing can achieve this, and exclusion testing is possible if you do not wish to learn your own status.
How quickly does it progress?
Typically over 15 to 20 years from the first motor signs, with wide variation between people.