NEET BIOLOGY

Detailed explanation-1: -HD is caused by a mutation in the gene for a protein called huntingtin. The defect causes the building blocks of DNA called cytosine, adenine, and guanine (CAG) to repeat many more times than they normally do. Most people have fewer than 27 CAG repeats in their HD gene, so they are not at risk for the disease.

Detailed explanation-2: -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-3: -The HTT gene provides instructions for making a protein called huntingtin. Although the exact function of this protein is unknown, it appears to play an important role in nerve cells (neurons) in the brain and is essential for normal development before birth.

Detailed explanation-4: -Huntington’s disease (HD) is unique among the other neurodegenerative diseases in that it is always inherited. HD is caused by abnormal huntingtin protein. The normal huntingtin protein contains multiple repeats of a sequence of three DNA bases, cytosine-adenine-guanine (CAG), which encodes the amino acid glutamine.