Huntington's disease

Definition

Huntington's disease is a hereditary neurodegenerative disorder caused by a mutation in the HTT gene, leading to the progressive breakdown of nerve cells in the brain. This condition follows an autosomal dominant inheritance pattern, meaning that only one copy of the mutated gene from an affected parent can lead to the disorder in offspring, showcasing how genetic traits are passed down through generations.

5 Must Know Facts For Your Next Test

1. Huntington's disease typically manifests in mid-adulthood, with symptoms including movement disorders, cognitive decline, and psychiatric issues.
2. The HTT gene mutation responsible for Huntington's disease involves an abnormal increase in CAG repeats, which leads to the production of a malfunctioning huntingtin protein.
3. Individuals with one affected parent have a 50% chance of inheriting the disease due to its autosomal dominant inheritance pattern.
4. Genetic testing can confirm the presence of the HTT gene mutation even before symptoms appear, allowing for early intervention and planning.
5. Currently, there is no cure for Huntington's disease, but treatments are available to manage symptoms and improve quality of life.

Review Questions

• How does the autosomal dominant inheritance pattern affect the likelihood of inheriting Huntington's disease?
  • In autosomal dominant inheritance, only one copy of the mutated gene is required for a person to develop the disorder. This means that if one parent has Huntington's disease, each child has a 50% chance of inheriting the mutated HTT gene. The presence of just one affected gene is sufficient to trigger the symptoms of the disease, making its transmission straightforward across generations.
• Discuss the role of CAG repeat expansions in the pathology of Huntington's disease and how it relates to neurodegeneration.
  • CAG repeat expansions in the HTT gene lead to an abnormal version of the huntingtin protein that is toxic to neurons. The resulting accumulation of this toxic protein disrupts cellular functions and ultimately causes neurodegeneration. As neurons break down over time, individuals experience progressive movement disorders, cognitive decline, and emotional disturbances characteristic of Huntington's disease.
• Evaluate current approaches to managing Huntington's disease and their implications for patient care and quality of life.
  • Current management strategies for Huntington's disease focus on alleviating symptoms since there is no cure. This includes pharmacological treatments for movement disorders and psychiatric symptoms, as well as physical therapy to maintain mobility. Psychosocial support is crucial for both patients and families to cope with the emotional impact of the diagnosis. As research continues into potential therapies that target the underlying genetic cause, improving quality of life remains a priority in patient care.

Related terms

Autosomal Dominant: A mode of inheritance where only one copy of a mutated gene is sufficient to cause a disorder, often seen in conditions like Huntington's disease.

Neurodegeneration: The progressive loss of structure or function of neurons, which is a key feature of Huntington's disease and other similar disorders.

CAG Repeats: A specific sequence of DNA repeats that is expanded in the HTT gene mutation responsible for Huntington's disease, leading to toxic protein production.