It is a neurodegenerative genetic
affects muscle coordination and leads
to cognitive decline and psychiatric
Chorea- abnormal involuntary writhing
Huntington’s Disease is also called
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
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
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
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,
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
• 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
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
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
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.