What are the chances of a person with huntigtons disease passing the disease to their offspring?

Answer 1

Huntington's disease is passed to offspring because it is a genetic mutation. Chromosome number four contains a gene called IT15 that codes for the amino acid in glutamine in the protein huntingtin. The nucleotide triplet that codes for this (CAG) usually repeats 11-34 times, but in a Huntington's gene it repeats 37-121 times. This "stutter" can lengthen when passed on through heredity, therefore increasing the chance that a person will have the disease.

Answer 2

Huntington's disease is caused by a dominant mutation on either of the two copies of a gene called Huntingtin, which means any child of an affected parent has a 50% risk of inheriting the disease. In rare situations where both parents have an affected gene, or either parent has two affected copies, this risk is greatly increased.

(http://en.wikipedia.org/wiki/Huntington's_disease)