2-Minute Neuroscience: Huntington's disease

Summary

This brief neuroscience video explains Huntington's disease, a fatal and incurable neurodegenerative disorder. Symptoms often begin in middle age and include movement problems such as chorea, muscle rigidity, and difficulty speaking or swallowing, along with cognitive and psychiatric issues like dementia and depression. Huntington's is caused by a dominant mutation in the huntingtin gene, leading to excessive repeats of a DNA sequence. This mutation results in the accumulation of faulty proteins in neurons, contributing to brain cell degeneration, especially in the basal ganglia.

Takeaways

• 🧠 Huntington's disease symptoms typically begin in middle age, affecting personality, cognition, and movement.
• 🤸‍♂️ Early movement symptoms include chorea, which is characterized by uncontrolled, jerky movements.
• ⚖️ As the disease progresses, coordination and balance become impaired, alongside muscle rigidity and difficulties with speech and swallowing.
• 🧓 Cognitive decline and psychiatric symptoms such as dementia and depression are common in advanced stages.
• ❌ Huntington's disease is currently incurable and fatal.
• 🔍 The condition is associated with neurodegeneration, particularly in the basal ganglia, though other brain areas are affected too.
• 🧬 The root cause of Huntington's disease is a mutation in the huntingtin gene, which is a dominant mutation.
• 👶 Children of an affected parent have a 50% chance of inheriting the mutated gene and developing the disease.
• 🔢 The mutation involves an excess number of trinucleotide repeats (CAG repeats) in the gene, and 40 or more repeats guarantees the development of the disease.
• 🧪 Mutated huntingtin proteins tend to cluster inside neurons, potentially contributing to increased neurodegeneration.

Q & A

What are the early symptoms of Huntington's disease?

The early symptoms often involve subtle changes in personality, cognition, and movement.

What movement problems are associated with advanced stages of Huntington's disease?

Advanced stages include movement problems such as chorea (uncontrolled, spasmodic movements), impaired coordination and balance, muscle rigidity, and difficulty speaking or swallowing.

What cognitive and psychiatric symptoms can occur in Huntington's disease?

Cognitive symptoms include dementia, while psychiatric symptoms can include depression.

Is there a cure for Huntington's disease?

No, Huntington's disease is currently incurable and fatal.

Which part of the brain is most affected by neurodegeneration in Huntington's disease?

The basal ganglia are strongly affected, but other regions of the brain also experience neurodegeneration.

What causes Huntington's disease at the genetic level?

Huntington's disease is caused by a mutation in the huntingtin gene, specifically involving a trinucleotide repeat (cytosine, adenine, guanine) that is expanded in the mutated gene.

What is the inheritance pattern of Huntington's disease?

Huntington's disease is caused by a dominant mutation, meaning if one parent has the disease, their child has a 50% chance of developing it.

How does the number of trinucleotide repeats affect Huntington's disease risk?

The higher the number of repeats in the huntingtin gene, the greater the risk of developing the disease. Individuals with 40 or more repeats will develop Huntington's disease.

What happens to the mutated huntingtin protein in the brain?

The mutated huntingtin proteins tend to form clusters within neurons, which are difficult for brain enzymes to remove. These clusters may contribute to neurodegeneration.

How are the accumulation of huntingtin protein clusters related to neurodegeneration?

The accumulation of huntingtin protein clusters in the brain is associated with increased neurodegeneration, though the exact mechanisms are still being studied.