Huntington disease is an autosomal dominant disorder that leads to progressive degeneration of brain cells. There is no effective treatment for the disorder and individuals usually die in their 40s or 50s, 10 to 15 years after the onset of symptoms. Which of these statements about Huntington disease is true?
A) As an autosomal dominant disease, Huntington disease is expressed only if both parents carry the trait.
B) Huntington disease usually skips a generation.
C) Researchers have located the gene for Huntington disease on chromosome 9.
D) Huntington disease usually appears during the teenage years.
E) Huntington disease is caused by a mutated copy of the gene for a protein called huntingtin.

Question

Quizplus · Accepted Answer

Huntington disease is caused by a mutation in the gene that codes for the protein huntingtin, located on chromosome 4, not chromosome 9. It does not require both parents to carry the trait to be expressed, does not typically skip generations, and although it can appear in the teenage years, it more commonly presents in mid-adult life.

Huntington Disease Is an Autosomal Dominant Disorder That Leads to Progressive