Genetics: Analysis and Principles 5th Edition by Robert Brooker

Exercise 22

Huntington disease is a rare dominant trait that causes neuro-degeneration later in life. A man in his thirties, who already has three children, discovers that his mother has Huntington disease though his father is unaffected. What are the following probabilities
a. That the man in his thirties will develop Huntington disease
b. That his first child will develop Huntington disease
c. That one out of three of his children will develop Huntington disease.