Presentation on Huntington's disease.pptx

Huntington’s Disease
It is basal ganglia disease. It is caused by degeneration of caudate nucleus and putamen, especially of GABAergic and acetylcholinergic neurons.
A Brief History of Huntington's Disease
Huntington's disease (HD) is named after George Huntington, who described it among residents of East Hampton, Long Island in 1872. It is a hereditary neurodegenerative disease. In 1993, a collaborative group of investigators discovered the gene that causes HD. As a result of this discovery it is now possible to diagnose HD with blood or tissue samples.
Detail of Degenerated Parts of the Brain during Huntington’s Disease
The detail of degenerated parts of the brain during huntington’s disease are given below:
Caudate nucleus
The basal ganglia are a group of structures found deep within the cerebral hemispheres. The structures generally included in the basal ganglia are the caudate, putamen, and globus pallidus in the cerebrum, the substantia nigra in the midbrain, and the subthalamic nucleus in the diencephalon. Despite the name, the basal ganglia are not actually ganglia.
The separate nuclei of the basal ganglia all have extensive roles of their own in the brain, but when referring to them as one network the function most frequently associated with the basal ganglia involves movement.
The basal ganglia receive information from the cortex, much of which is sent first to the caudate and putamen (which together are often referred to as the striatum). After the information is processed by the basal ganglia, it is sent back to the cortex by way of the thalamus. Thus, the pathway from the cortex to the basal ganglia and then back to the cortex via the thalamus forms a loop.
In simplistic terms, the functions of the basal ganglia in motor control are to facilitate movement and inhibit competing movements. For example, when someone tries to make an intentional movement like reaching for a pencil, the basal ganglia help to facilitate the movement by allowing motor plans associated with that movement (reaching and grasping in this case) to be activated. At the same time, the basal ganglia cause motor plans that might counteract the movement (perhaps flexing in this case) to be inhibited. The result is a smooth and fluid movement.
Putamen
The putamen is a round structure located at the base of the forebrain (telencephalon). The putamen and caudate nucleus together form the dorsal striatum. It is also one of the structures that composes the basal ganglia. A primary function of the putamen is to regulate movements at various stages (e.g. preparation and execution) and influence various types of learning. It employs GABA, acetylcholine, and enkephalin to perform its functions.
GABA
Gamma-Amino Butyric acid (GABA) is an amino acid which acts as a neurotransmitter in the central nervous system. It inhibits nerve transmission in the brain, calming nervous activity.
Acetylecholine
Use acetylcholine as a neurotransmitter to innervate cholinergic neurons.

1. Huma Saeed 31005

2. Huntington’s Disease In this degenerative disorder; Degeneration in caudate nucleus and putamen .

3. GABA Gamma-Amino Butyric acid ( GABA ) is an amino acid which acts as a neurotransmitter in the central nervous system. It inhibits nerve transmission in the brain, calming nervous activity. As a supplement it is sold and promoted for these neurotransmitter effects as a natural  tranqilizer (anti-anxiety agent).

4. Acetylecholine use acetylcholine as a neurotransmitter to innervate (or excite) cholinergic neurons (neurons expressing nicotinic acetylcholine receptors ) Acetylcholine in the serum exerts a direct effect on vascular tone by binding to  muscarinic receptors present on vascular endothelium. These cells respond by increasing production of nitric oxide, which signals the surrounding smooth muscle to relax, leading to  vasodilation .

5. symptoms Involuntarily movements especially jerky limb movements may fragments of purposeful movements Chorea(dance like movement)

6. Types of Huntington's Disease Huntington's disease has two subtypes: Adult-onset Huntington's disease usually develop symptoms in their mid-40s and 50s. Juvenile Huntington's disease Children and teenagers have this form of Huntington's disease, which is very rare

7. Development and course The symptoms of huntington’s disease usually begin in 30s and 40s Sometimes begin in the early 20s The first sign of neural degeneration occur in the putamen , in a specific group of inhibitory neurons This disease is progressive and eventually causes death

8. Etiology Physical Damage to GABAergic neurons and acetylcholinergic neurons removes some inhibitory control exerted on the premotor and supplementary motor area of the frontal cortex. Loss of this control leads to involuntary movements Lateral ventricle enlarge Striatum shrink

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10. Genetic It is a hereditary disorder Huntington’s disease is caused by a faulty gene on chromosome 4 The gene which produces a protein called Huntingtin , was discovered in 1993. In some way-which is not yet understood-the faulty gene leads to a damage of the nerve cells in areas of the brain, including the basal ganglia and cerebral cortex. This leads to gradual physical, mental and emotional changes

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12. . Each person whose parent has Huntington’s disease is born with a 50-50 chance of inheriting the faulty gene. Anyone who inherits the faulty gene will, at some stage, develop the disease

13. Experiment In cells of genetically altered HD mice that express long huntingtin and develop a disorder that closely resembels huntington’s disease Fragements of huntingtin begin to accumulate in the nucleus Which apparently triggers the production of caspase (killer enzyme), that plays a role in apoptosis, or programmed cell death It is found that HD mice lived longer if they were given a caspase inhibitor, which suppresses apoptosis

14. Psychological changes Anxiety and depression Irritability Apathy Impulsive behavior Obsessions/compulsions These changes may cause in elevation of suicidal rate

15. Cognitive changes Memory loss Executive dysfunction Treatment Medications for movement disorders Tetrabenazine Antipsychotic drugs Other medications- help suppress chorea Medications for psychiatric disorders Antidepressants

16. . Antipsychotic drugs  Mood-stabilizing drugs  Psychological support Psychotherapy Physical therapy Occupational therapy Speech therapy Caregivers are very important

17. Prognosis HD is a relentlessly progressive disorder, leading to disability and death, usually from an intercurrent illness. The mean age at death in all major series ranges from 51-57 years, but the range may be broader. Duration of illness varies considerably, with a mean of approximately 19 years. Most patients survive for 10-25 years after the onset of illness .