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Huntington disease

An evidence-led atlas of HTT CAG expansion, variable motor, cognitive, and psychiatric features, genetic testing, and multidisciplinary symptomatic care.

Huntington disease · Huntington's disease · HD

MONDO:0007739Public QA completeSource-bound · 4

Disease at a glance

Start with the essentials, then explore the patient and research views.

Public revision · 2a71827ffe9b

Disease class
Huntington disease is a progressive neurodegenerative disorder affecting movement, cognition, behavior, and mental health.
Core mechanism
It is caused by a CAG-repeat expansion in HTT and is inherited in an autosomal-dominant manner.
Genes or cause
Each child of an affected person has a 50% chance of inheriting the pathogenic expansion, regardless of sex.
Typical features
Chorea, impaired coordination, and changes in speech or swallowing can occur.
Variability
Depression, irritability, apathy, and changes in judgment or memory can occur before or after motor symptoms.
Diagnosis
Diagnosis is established by characteristic clinical findings and molecular confirmation of the HTT CAG expansion.
Management
Absence of a known family history does not exclude Huntington disease.
Treatment and research
Predictive testing before symptoms is offered to adults with detailed genetic counseling and voluntary informed consent.
Reading evidence
No current treatment stops disease progression; care supports symptoms, function, and safety.
Key caution
Medication can be considered for troublesome chorea after weighing benefit and adverse effects.

For patients and families

A structured guide for understanding the disease and preparing for clinical conversations.

At a glance

Huntington disease is a progressive neurodegenerative disorder affecting movement, cognition, behavior, and mental health.

Chorea, impaired coordination, and changes in speech or swallowing can occur.

How the disease works

It is caused by a CAG-repeat expansion in HTT and is inherited in an autosomal-dominant manner.

Each child of an affected person has a 50% chance of inheriting the pathogenic expansion, regardless of sex.

Why experiences vary

Depression, irritability, apathy, and changes in judgment or memory can occur before or after motor symptoms.

Diagnosis and management

Diagnosis is established by characteristic clinical findings and molecular confirmation of the HTT CAG expansion.

Treatment status

Absence of a known family history does not exclude Huntington disease.

Predictive testing before symptoms is offered to adults with detailed genetic counseling and voluntary informed consent.

Reading clinical trials

Follow-up needs multidisciplinary neurology, mental-health, rehabilitation, speech, nutrition, and social support.

Topics for a clinical visit

Clinical discussion should cover current symptoms, suicide risk, swallowing and driving safety, care planning, and implications of genetic testing.

Medical notice

This material is for disease education and is not a personal diagnosis or treatment instruction.

Evidence and sources

A trial registry status does not establish efficacy or regulatory approval.