AP BIOLOGY

Detailed explanation-1: -Huntington’s disease is an autosomal dominant disorder, which means that a person needs only one copy of the nontypical gene to develop the disorder. With the exception of genes on the sex chromosomes, a person inherits two copies of every gene-one copy from each parent.

Detailed explanation-2: -Huntington’s disease is caused by a faulty gene. Cells in parts of the brain are very sensitive to the effects of the faulty gene. This makes them function poorly and eventually die. A parent with the Huntington’s disease gene has one good copy of the gene and one faulty copy.

Detailed explanation-3: -The Genetic Cause of HD HD is caused by mutation in a gene located on chromosome 4. This gene is found in every human being, and contains a CAG repeat sequence. We have not yet discovered the gene’s normal function. In a case of HD, the gene contains an abnormally large number of CAG repeats.

Detailed explanation-4: -Huntington’s disease is caused by a mutation in the HD gene in which the same three bases? (CAG) are repeated many more times than normal. This is known as a CAG trinucleotide repeat expansion. In people who don’t have Huntington’s disease this section of CAG repeats in the gene is usually only repeated 10 to 35 times.

Detailed explanation-5: -It affects males and females equally and crosses all ethnic and racial boundaries. Typically, symptoms begin between age 30 and 55.