Huntington Disease in Kathmandu — Genetic Testing, Symptoms and Supportive Care

Huntington disease (HD) is an autosomal dominant genetic neurodegenerative disorder caused by expansion of a CAG trinucleotide repeat in the HTT gene. This mutation produces an abnormal huntingtin protein that leads to progressive degeneration in the basal ganglia and cerebral cortex. HD causes a characteristic triad of movement disorder, cognitive decline, and psychiatric symptoms, typically beginning in mid-adulthood.

Movement symptoms are often the first noticeable feature. Chorea — involuntary, dance-like movements — is the classic motor manifestation. Patients initially notice subtle fidgeting, restlessness, or clumsiness. Over time, chorea becomes more pronounced and may interfere with daily activities. Other motor features include dystonia (sustained muscle contractions causing abnormal postures), rigidity, bradykinesia (slowness of movement), and impaired balance. Eye movement abnormalities are also characteristic and can be detected on neurological examination even before other symptoms appear.

Dr. Jitendra Prasad Yadav — consultant neurologist & headache specialist at Kathmandu Neurology Clinic & Cognitive Center provides evidence-based evaluation for dementia.

Cognitive decline in HD primarily affects executive function — planning, organization, and mental flexibility. Memory for past events remains relatively preserved early in the disease, but difficulty with new learning, slowed thinking, and reduced attention become apparent. Cognitive changes progress slowly and eventually impact daily function, work performance, and independence.

Psychiatric symptoms are common and may precede motor symptoms by years. Depression occurs in up to 50% of HD patients. Anxiety, irritability, apathy, and obsessive-compulsive behaviors are also frequent. Psychosis occurs in a minority of patients. Suicide risk is elevated, particularly in early stages when patients are aware of the diagnosis but still functional.

Genetic testing for HD is available and definitive. The test measures the number of CAG repeats in the HTT gene. Normal alleles have 26 or fewer repeats. Reduced penetrance alleles (27-35 repeats) may not cause disease. Full penetrance alleles (36 or more repeats) will cause HD, with larger repeat expansions generally associated with earlier onset and more rapid progression. Genetic testing should be performed with appropriate genetic counselling, particularly for predictive testing in asymptomatic at-risk individuals.

Disease management is currently supportive, as there is no cure or disease-modifying treatment. Tetrabenazine and deutetrabenazine can help suppress chorea, though they may worsen depression and require careful monitoring. Antipsychotics may be used for severe chorea or psychosis. Depression and anxiety are treated with standard antidepressants. Cognitive support involves strategies to compensate for executive dysfunction.

At Kathmandu Neurology Clinic & Cognitive Center, Dr. Jitendra Prasad Yadav (NMC 8029) provides evaluation for suspected HD, coordinates genetic testing with appropriate counselling, and offers supportive management focusing on symptom control and quality of life. The clinic emphasizes genetic counselling and psychological support for patients and families.

This article is educational and does not replace individual medical advice.

**Frequently Asked Questions**

Q: Is Huntington disease hereditary? A: Yes, HD is an autosomal dominant genetic condition. Each child of a parent with HD has a 50% chance of inheriting the mutated gene. If the mutated gene is inherited, the person will develop HD at some point in their life (complete penetrance for alleles with 36+ CAG repeats).

Q: At what age does Huntington disease typically start? A: HD most commonly begins between ages 30 and 50, but onset can range from childhood to late adulthood. Juvenile HD (onset before age 20) tends to progress more rapidly and often presents with different symptoms, including rigidity and seizures rather than chorea.

Q: What are the early symptoms of Huntington disease? A: Early symptoms often include subtle involuntary movements (chorea), mild cognitive changes (difficulty with planning and organization), irritability or depression, and slight clumsiness. Symptoms typically progress gradually over years.

Q: How is Huntington disease diagnosed? A: Diagnosis is confirmed by genetic testing showing expansion of CAG repeats in the HTT gene. Clinical evaluation, family history, and neurological examination support the diagnosis but genetic testing is definitive. Appropriate genetic counselling is essential before testing.

Q: Is there a cure for Huntington disease? A: Currently, there is no cure for HD. Treatment is supportive and focuses on managing symptoms — chorea, psychiatric symptoms, and cognitive changes. Research into disease-modifying therapies is ongoing, but no treatment has yet been proven to slow or stop disease progression.

Q: Should family members of HD patients get genetic testing? A: Predictive genetic testing for at-risk asymptomatic individuals is a complex decision that requires careful genetic counselling. Testing is not recommended for minors. The decision to test is personal and should consider psychological impact, family planning, and potential discrimination. Testing should be voluntary and informed.