Write 5 pages thesis on the topic overview of huntingtons disease. The incidence of Huntington disease is estimated to be 3-7 per 100,000 persons of European descent. It is less common in other populations. The condition is caused by a genetic mutation that causes a defect in chromosome 4. The defect is manifested by an abnormal reoccurrence of the CAG repeat on the DNA. This reoccurrence occurs up to 120 times compared with the normal 10-28 repeats (Vargas, Carod-Artal, Bomfim, Vázquez-Cabrera, & Dantas-Barbosa, 2003). These repeats increase with heredity and the manifestations of the condition, therefore, worsen with generations. Similarly, the age of onset tends to reduce as the condition is passed along the family line. The heredity probability from a parent who has the condition is 50%, when both parents have the condition. the children will have the disease and will pass it to their children (Folstein, 1989).

Huntington disease is inherited in an autosomal dominant fashion. This means that if a copy of the repetitive gene is present in each cell, the condition will appear. Although the disease is hereditary, rare cases of severe mutations leading to the development of the condition have been reported.

With the inheritance f the condition, the symptoms do not appear at birth. They appear between the ages of 30 and 50. The cardinal symptom of the condition is an abnormal and uncontrolled movement of the limbs, head, face, and the upper trunk (Vargas et al., 2003). These are because of the degeneration of the cells in the control centers in the brain that govern the voluntary movements of these parts.

The symptoms can therefore be categorized as movement disorders, cognitive disorders, and psychiatric disorders. In movement disorders, Huntington’s disease manifest as involuntary movement of limbs (chorea), speech problems, muscular rigidity, abnormal ocular movement, and impaired gait and posture. Cognitive symptoms include impaired reasoning, judgment, memory, concentration, and general human organization.&nbsp.&nbsp.