--- title: "Huntington's Disease | Intro to Psychology" description: "Huntington's disease is an inherited neurodegenerative disorder that causes chorea, cognitive decline, and mood changes in Intro to Psychology." canonical: "https://fiveable.me/intro-psychology/key-terms/huntingtons-disease" type: "key-term" subject: "Intro to Psychology" unit: "Unit 3" --- # Huntington's Disease | Intro to Psychology ## Definition Huntington's disease is an inherited neurodegenerative disorder that causes involuntary movement, cognitive decline, and emotional changes. In Intro to Psychology, it is a clear example of how genes can affect brain function and behavior. ## What It Is Huntington's disease is a genetic neurodegenerative disorder covered in Intro to Psychology when you study human genetics, brain function, and abnormal behavior. It happens when a person inherits a faulty version of the huntingtin gene, which leads to progressive damage in certain brain cells, especially in areas involved in movement, thinking, and mood. The inheritance pattern is autosomal dominant, which means one copy of the altered gene is enough for the disorder to appear. That makes Huntington's disease different from recessive conditions, where a person usually needs two affected copies. In family trees, you often see the trait passed from one generation to the next without skipping many generations. A big part of the disorder is the buildup of an abnormal huntingtin protein. Over time, this protein damages neurons and the brain loses some of its ability to coordinate movement, regulate emotions, and support memory and planning. Symptoms often begin in adulthood, commonly between ages 30 and 50, which is why someone may seem healthy for years before signs start to show. The most visible symptom is chorea, which means sudden, involuntary, dance-like movements. But Huntington's disease is not just a movement disorder. People can also have irritability, depression, anxiety, personality changes, and trouble with attention, decision-making, and other thinking skills. For psychology, this term sits at the point where biology and behavior meet. It shows that mental processes are not separate from the brain, and that a change in DNA can affect movement, cognition, and emotion all at once. There is no cure yet, but treatment can ease symptoms and support daily functioning. ## Why It Matters Huntington's disease matters in Intro to Psychology because it gives you a concrete example of how genes influence behavior through the brain. When you study human genetics, this disorder shows that inheritance is not just about eye color or blood type. A single faulty gene can lead to major changes in movement, memory, personality, and mood. It also connects directly to the course's ideas about neurodegenerative disorders. Huntington's disease helps you see what happens when neurons break down over time instead of recovering after injury. That makes it useful for understanding the difference between temporary symptoms and progressive conditions. This term also comes up when your class talks about abnormal psychology and the limits of a simple mind versus body split. A person with Huntington's disease may experience depression, irritability, or cognitive decline, but those symptoms are tied to a physical change in the brain. That is a good reminder that psychological symptoms can have biological causes. When you read a case study, Huntington's disease can help you connect inheritance patterns, symptom progression, and brain changes into one explanation instead of treating them as separate facts. ## Connections ### Trinucleotide Repeat Disorder Huntington's disease is one of the best-known trinucleotide repeat disorders. In this type of disorder, a short DNA sequence is repeated too many times, which changes how the gene works. That extra repetition is what makes the disorder progressive and inherited, and it helps explain why symptoms may not show up until adulthood. ### Neurodegenerative Disorder This term fits Huntington's disease because the disorder gets worse as neurons are damaged and die over time. In Intro to Psychology, neurodegenerative disorders are useful for studying how brain breakdown affects cognition, emotion, and movement. Huntington's disease is a clear example because it affects all three. ### Chorea Chorea is the movement symptom people often notice first in Huntington's disease. If a question asks about sudden, jerky, dance-like movements, chorea is the vocabulary word you want. It is a symptom, not the disease itself, so you use it to describe one visible effect of the disorder. ### [Epigenetics](/intro-psychology/key-terms/epigenetics) Huntington's disease is caused by an inherited gene mutation, so it is not an epigenetic disorder in the usual sense. Still, epigenetics is a useful comparison because both topics show that gene expression and behavior are not fixed in a simple way. In psychology, this helps you separate inherited DNA changes from changes in gene activity. ## On the AP Exam A quiz question might ask you to identify Huntington's disease from a description of adult-onset chorea, memory decline, and an autosomal dominant inheritance pattern. You may also see it in a short case study where you have to trace symptoms from gene mutation to brain damage to behavior changes. If your teacher uses family pedigree charts, Huntington's disease is a classic example because it often appears in multiple generations. On essays or short responses, you might explain how one genetic mutation can affect both movement and cognition, or compare it with a disorder that follows a recessive pattern. The main move is to connect the gene, the brain, and the symptoms instead of listing facts separately. ## Huntington's Disease vs Chorea Huntington's disease is the inherited disorder, while chorea is one symptom of that disorder. If a question describes the disease as a whole, look for the genetic cause and the full pattern of cognitive, emotional, and movement changes. If it only describes the jerky movement, the answer is chorea. ## Key Takeaways - Huntington's disease is an inherited neurodegenerative disorder that affects movement, thinking, and mood. - It is autosomal dominant, so one altered copy of the gene is enough to cause the condition. - The disease is linked to an abnormal huntingtin protein that damages neurons over time. - Chorea is the movement symptom most often associated with Huntington's disease, but cognitive and emotional changes are also common. - In Intro to Psychology, it is a useful example of how genes and brain changes can shape behavior. ## FAQs ### What is Huntington's disease in Intro to Psychology? Huntington's disease is a genetic neurodegenerative disorder that causes uncontrolled movements, cognitive decline, and emotional changes. In Intro to Psychology, it is used to show how an inherited mutation can affect brain function and behavior over time. ### Is Huntington's disease dominant or recessive? Huntington's disease is autosomal dominant. That means a person only needs one altered copy of the gene from a parent to develop the disorder. This is why it often shows up across several generations in a family tree. ### How is Huntington's disease different from chorea? Huntington's disease is the full disorder, and chorea is one of its symptoms. Chorea refers to the sudden, involuntary, dance-like movements, while Huntington's also includes memory problems, personality changes, and psychiatric symptoms. ### How does Huntington's disease show up on a psychology test? You might see a case description, a pedigree chart, or a question asking which disorder causes adult-onset movement problems and cognitive decline. The test move is to recognize the autosomal dominant inheritance pattern and connect it to brain degeneration and behavior changes. ## Related Study Guides - [3.1 Human Genetics](/intro-psychology/unit-3/1-human-genetics/study-guide/Agif4EWGIgIS9jwU) ## About This Document Canonical Fiveable pages are available as Markdown at the same path plus `.md`. - [llms.txt](https://fiveable.me/llms.txt): index of Fiveable's sections and URL patterns - [llms-full.txt](https://fiveable.me/llms-full.txt): complete subject and unit listing - [MCP server](https://fiveable.me/mcp): call Fiveable as tools instead of fetching pages (`https://fiveable.me/api/mcp`) - [MCP server for AP teachers](https://fiveable.me/mcp/teachers): a teacher's classes, assignments and AP-rubric grading (`https://fiveable.me/api/mcp/teacher`) ## Structured Data ```json {"@context":"https://schema.org","@graph":[{"@type":"LearningResource","@id":"https://fiveable.me/intro-psychology/key-terms/huntingtons-disease#resource","name":"Huntington's Disease | Intro to Psychology","url":"https://fiveable.me/intro-psychology/key-terms/huntingtons-disease","learningResourceType":"Concept explainer","educationalLevel":"AP® / High School","about":{"@id":"https://fiveable.me/intro-psychology/key-terms/huntingtons-disease#term"},"audience":{"@type":"EducationalAudience","educationalRole":"student"},"dateModified":"2026-07-03T02:22:12.771Z","isPartOf":{"@type":"Collection","name":"Intro to Psychology Key Terms","url":"https://fiveable.me/intro-psychology/key-terms"},"publisher":{"@type":"Organization","name":"Fiveable","url":"https://fiveable.me"}},{"@type":"DefinedTerm","@id":"https://fiveable.me/intro-psychology/key-terms/huntingtons-disease#term","name":"Huntington's Disease","description":"Huntington's disease is an inherited neurodegenerative disorder that causes involuntary movement, cognitive decline, and emotional changes. 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