It is a neurodegenerative genetic disorder.

affects muscle coordination and leads to cognitive decline and psychiatric problems.

Chorea- abnormal involuntary writhing movements

Huntington’s Disease is also called “Huntington’s Chorea”

 Huntington's disease has been recognized as a disorder since at least the Middle Ages

The first thorough description of the disease was by George Huntington in 1872. 

 Expansion of a CAG triplet repeat stretch within the Huntingtin gene results in a different (mutant) form of the protein, which gradually damages cells in the brain, through mechanisms that are not fully understood.

HD results from genetically programmed degeneration of nerve cells, called neurons,* in certain areas of the brain. 

 Specifically affected are cells of the basal ganglia, structures deep within the brain that have many important functions, including coordinating movement.

Within the basal ganglia, HD especially targets neurons of the striatum, particularly those in the caudate nuclei and the pallidum. 

Also affected is the brain's outer surface, or cortex, which controls thought, perception, and memory.

passed from parent to child through a mutation or misspelling in the normal gene.

The gene that produces HD lies on chromosome 4, one of the 22 non-sex-linked, or "autosomal," pairs of chromosomes.

small sequence of DNA on chromosome 4 in which several base pairs are repeated many, many times

In people with HD, the sequence abnormally repeats itself dozens of times ( three DNA bases).

cause a new genetic mutation-an alteration in the gene (occurs during sperm development).

Autosomal dominant disorder -  only one copy of the defective gene, inherited from one parent, is necessary to produce the disease.

Early signs of the disease: mood swings or uncharacteristically irritable,

apathetic, passive, depressed, or angry.  hostile outbursts or deep bouts

of depression. having trouble driving, learning new things,

remembering a fact, answering a question, or making a decision.

As disease progresses:• uncontrolled movements in the

fingers, feet, face, or trunk.•  mild clumsiness or problems with

balance•  stumble or appear uncoordinated• speech is slurred • vital functions, such as swallowing,

eating, speaking, and especially walking, continue to decline. 

• Some individuals cannot recognize other family members. 

The most common causes of death are infection (most often pneumonia), injuries related to a fall, or other complications.

Take the family history or genealogy Using a blood sample Undergo a brain imaging test. Computed tomography (CT) and magnetic

resonance imaging (MRI) 

Tetrabenazine- to treat the chorea Haloperidol- antipsychotic drugs Clonazepam- alleviate choreic movements,

control hallucinations and delusions.  fluoxetine sertraline, nortriptyline – for

depression Tranquilizers- help control anxiety Lithium- for pathological excitements and

severe mood swings

 The worldwide prevalence of HD is 5–10 cases per 100,000 persons, but varies greatly geographically as a result of ethnicity, local migration and past immigration patterns.

Prevalence is similar for men and women. The rate of occurrence is highest in peoples

of Western European descent, averaging around 7 per 100,000 people, and is lower in the rest of the world, e.g. one per million people of Asian and African descent.

 A 2013 epidemiological study of the prevalence of Huntington's Disease in the UK between 1990 and 2010 found that the average prevalence for the UK was 12.3 per 100,000.