Huntington’s disease usually causes movement, cognitive and psychiatric disorders with a wide spectrum of signs and symptoms. Some of these include slow or abnormal eye movements, impaired gait, posture and balance. It affects an estimated 3 to 7 per 100,000 people from the general population.

Huntington’s disease has autosomal dominant inheritance, which means that a person needs only one copy of the defective gene to develop the disorder. In this type of inheritance pattern, each offspring of an affected individual has a 50% risk of inheriting the mutant allele. As the gene is passed from parent to child, the size of the CAG trinucleotide repeat may lengthen and is usually associated with an earlier onset of signs and symptoms. This probability is sex-independent.

Currently there are no available treatments for Huntington’s Disease. The time from disease emergence to death is often about 10 to 30 years. However there are certain medications that suppress certain symptoms such as involuntary movements, control delusions and violent outbursts.

References:

http://www.mayoclinic.org/diseases-conditions/huntingtons-disease/symptoms-causes/dxc-20321436

https://en.wikipedia.org/wiki/Huntington%27s_disease#Inheritance

https://ghr.nlm.nih.gov/condition/huntington-disease#statistics