What is Huntingtons Disease

Huntington’s disease is a progressive, hereditary neurodegenerative disorder caused by a genetic mutation that leads to the breakdown of nerve cells in the brain. It significantly impacts physical movement, cognitive function, and emotional health, typically manifesting in mid-life between the ages of 30 and 50.

What exactly is Huntington’s disease?

Huntington’s disease is a rare, inherited condition that causes the progressive degeneration of nerve cells in the brain, particularly in the basal ganglia and cerebral cortex. Because these areas control movement, emotion, and cognitive processes, individuals with Huntington’s disease experience a wide range of debilitating symptoms. Over time, the condition leads to a decline in functional abilities, affecting a person’s ability to walk, think, talk, and manage their emotions.

How does Huntington’s disease affect the body?

The impact of Huntington’s disease is multi-systemic, primarily targeting the central nervous system. The physical, cognitive, and psychiatric symptoms often appear gradually:

• Movement disorders: Involuntary jerking or writhing movements (chorea), muscle rigidity, and difficulties with speech and swallowing.


• Cognitive decline: Challenges with executive functions, such as planning, organizing, focusing on tasks, and impulse control.


• Psychiatric symptoms: Depression is the most common, but individuals may also experience irritability, apathy, social withdrawal, and, in some cases, obsessive-compulsive behaviors.

What causes Huntington’s disease?

Huntington’s disease is caused by a specific mutation in the HTT gene, which provides instructions for making a protein called huntingtin. In affected individuals, the gene contains an abnormally long repetition of a DNA segment (CAG trinucleotide repeat). This causes the production of an elongated, toxic version of the huntingtin protein. This toxic protein accumulates in neurons, eventually causing them to malfunction and die. It is an autosomal dominant condition, meaning a child of an affected parent has a 50% chance of inheriting the mutated gene.

Who is typically affected by this condition?

The prevalence of Huntington’s disease varies by population but is estimated to affect approximately 5 to 10 per 100,000 people in Western countries. While symptoms most commonly begin between the ages of 30 and 50, there are two distinct clinical presentations: the adult-onset form, which is more common, and the juvenile-onset form, which occurs in children or teenagers and typically progresses more rapidly.

How is Huntington’s disease different from other disorders?

While other conditions may cause movement disorders or dementia, Huntington’s disease is distinct due to its specific genetic signature and the unique combination of the "triad" of symptoms: movement dysfunction, cognitive decline, and psychiatric disturbances. Unlike Parkinson’s disease, which primarily involves tremor and bradykinesia, the movement symptoms in Huntington’s disease are characterized by chorea (involuntary, dance-like movements) and are inextricably linked to the characteristic family history of the disease.

Currently, 39 people with Huntington’s disease have joined the DiseaseMaps community to share their experiences and support one another through the challenges of this diagnosis.

Next steps

• Consult a neurologist or a movement disorder specialist to discuss clinical management and symptom support.


• Seek genetic counseling to understand the implications of the diagnosis for family members.


• Join a local or online support group, such as the DiseaseMaps community, to connect with others facing similar experiences.


• Explore clinical trials through platforms like the Huntington’s Disease Society of America (HDSA) to learn about the latest research and potential therapeutic interventions.

Medical disclaimer: This content is for informational purposes only and does not constitute medical advice, diagnosis, or treatment; always seek the advice of a qualified healthcare provider with any questions regarding a medical condition.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Huntington disease overview.


• Orphanet: Portal for rare diseases and orphan drugs (ORPHA:399).


• Online Mendelian Inheritance in Man (OMIM): Entry #143100.


• Huntington’s Disease Society of America (HDSA): Patient resources and clinical research updates.