Huntington's disease

Definition

Huntington's disease is a genetic disorder caused by a mutation in the HTT gene, leading to progressive neurodegeneration and motor dysfunction. This autosomal dominant condition typically manifests in mid-adulthood, affecting an individual's ability to control movements, cognitive function, and emotional stability. The connection between this disease and genetic disorders highlights the impact of inherited traits on health, as well as the importance of genetic counseling for affected families.

5 Must Know Facts For Your Next Test

1. Huntington's disease is characterized by a triad of symptoms: motor dysfunction (chorea), cognitive decline, and psychiatric issues.
2. The average age of onset for Huntington's disease is around 30 to 50 years old, but symptoms can appear earlier or later depending on the individual.
3. Each child of an affected individual has a 50% chance of inheriting the mutated gene due to its autosomal dominant nature.
4. As the disease progresses, individuals may require assistance with daily activities due to severe motor and cognitive impairments.
5. Genetic testing can confirm the presence of the CAG repeat expansion in the HTT gene, allowing for early diagnosis and family planning options.

Review Questions

• How does the inheritance pattern of Huntington's disease affect family planning for those with a family history of the disorder?
  • Huntington's disease follows an autosomal dominant inheritance pattern, meaning that an affected individual has a 50% chance of passing the mutated gene to each child. This significant risk impacts family planning decisions, as prospective parents may consider genetic counseling and testing to understand their risks better. Families may also explore options such as prenatal testing or in vitro fertilization with preimplantation genetic diagnosis to avoid passing on the disorder.
• Discuss the neurological changes that occur in individuals with Huntington's disease and their implications for patient care.
  • Huntington's disease leads to neurodegeneration primarily affecting the basal ganglia, which is responsible for movement control. As neurons in this area deteriorate, patients experience chorea (involuntary movements), rigidity, and coordination issues. These neurological changes necessitate comprehensive patient care that includes physical therapy to manage movement symptoms, cognitive support strategies for memory and decision-making issues, and psychiatric interventions to address mood disorders such as depression and anxiety.
• Evaluate the potential impact of emerging therapies on the management of Huntington's disease and the lives of affected individuals.
  • Emerging therapies for Huntington's disease focus on targeting the underlying genetic mutation and slowing neurodegeneration. Approaches such as gene silencing techniques aim to reduce levels of the mutant huntingtin protein, potentially altering the disease course. If successful, these therapies could significantly improve quality of life for patients by delaying symptom onset or progression. Such advancements also raise ethical considerations regarding access to treatment and implications for those at risk but not yet symptomatic.

Related terms

Autosomal Dominant: A mode of inheritance where only one copy of a mutated gene from an affected parent can cause the disease in offspring.

Neurodegeneration: The progressive loss of structure or function of neurons, which is a hallmark of diseases like Huntington's.

CAG Repeats: The specific sequence of nucleotides repeated in the HTT gene that, when expanded beyond a normal range, causes Huntington's disease.