What Huntington disease is
Huntington disease is an autosomal dominant genetic disorder caused by CAG trinucleotide repeat expansion in the HTT gene on chromosome 4. The mutation produces an abnormal huntingtin protein that causes progressive neurodegeneration, particularly in the basal ganglia and cerebral cortex. HD is fully penetrant � individuals with the mutation will develop symptoms if they live long enough, typically between ages 30 and 50.
The classic triad of HD includes movement disorder (chorea � involuntary dance-like movements, dystonia, bradykinesia), cognitive decline (executive dysfunction, slowed processing, eventually dementia), and psychiatric symptoms (depression, anxiety, irritability, psychosis). Juvenile HD (onset before age 20) presents more rapidly with parkinsonism and seizures rather than chorea. Genetic testing and genetic counselling are essential given the hereditary nature and implications for family members.
- Autosomal dominant genetic disorder
- CAG repeat expansion in HTT gene
- Chorea � involuntary dance-like movements
- Cognitive decline and psychiatric symptoms
- Family counselling and genetic testing essential
Related: Movement Disorder → · Dr. Jitendra Knowledge Hub → · ICHD-3 Topic →
Evaluation and management
Evaluation begins with detailed family history (autosomal dominant inheritance pattern), neurological examination characterising movement disorder (chorea, dystonia, parkinsonism), cognitive assessment, and psychiatric screening. Genetic testing confirms the diagnosis by detecting CAG repeat expansion in the HTT gene. Predictive testing for at-risk asymptomatic individuals requires genetic counselling before and after testing.
Management is symptomatic as there is no cure for HD. Tetrabenazine or deutetrabenazine (VMAT2 inhibitors) reduce chorea. Antipsychotics may help with psychiatric symptoms and chorea. Depression and anxiety are treated with appropriate antidepressants. Cognitive decline and dementia are managed with environmental modifications, caregiver support, and eventually long-term care planning. Physical therapy maintains mobility and prevents contractures. Dr. Jitendra Prasad Yadav (NMC 8029) provides HD evaluation, genetic counselling referral, and symptomatic management at Kathmandu Neurology Clinic, Durbar Marg, Opposite of Yak & Yeti Hotel.
| Symptom Domain | Manifestations | Treatment Approach |
|---|---|---|
| Movement disorder | Chorea, dystonia, parkinsonism | Tetrabenazine, deutetrabenazine, antipsychotics |
| Cognitive decline | Executive dysfunction, dementia | Environmental modification, caregiver support |
| Psychiatric symptoms | Depression, anxiety, irritability, psychosis | Antidepressants, antipsychotics, counselling |
| Functional impact | Mobility decline, swallowing difficulty | Physical therapy, speech therapy, safety planning |