Huntington's Disease, or Huntington's Chorea, is a rare autosomal dominant disease that results in the slow deterioration of the physical and mental abilities of the affected person. Experts estimate that one in every 10,000 people (about 30,000 Americans) suffer from Huntington disease and another 150,000 are at risk for developing it. Many describe the symptoms of HD as having ALS, Parkinson’s and Alzheimer’s – simultaneously.

Symptoms usually appear between the ages of 30 to 50, and worsen over a 10 to 25 year period. Ultimately, the weakened individual succumbs to pneumonia, heart failure or other complications. Every person who inherits the HD gene will eventually develop the disease. Over time, HD affects the individual’s ability to reason, walk and speak. Since the disease does not manifest until a late age, an affected person will often have children already. You can take genetic tests to see if you are at risk for the disease. Use this pedigree to answer the questions about Huntington’s.
1. Using the letters H and h, what is the genotype for each of the following people?

Person 1: _______

Person 2: _______

Person 3: ________

2. Is Huntington’s dominant or recessive? Use evidence from the reading and pedigree to support your answer.


3. Person 3 has a child with someone who does not have Huntington’s. Complete a Punnett Square to determine the chance their offspring will have Huntington’s.

Chance their offspring will have Huntington’s=