U.S. National Library of Medicine Huntington disease - Genetics Home Reference National Institutes of Health April 20, 2018https://ghr.nlm.nih.gov/condition/huntington-disease#statistics Mayo Clinic Huntington's disease Mayo Foundation for Medical Education and Research June 13, 2017 April 20, 2018https://www.mayoclinic.org/diseases-conditions/huntingtons-disease/symptoms-causes/syc-20356117 What is HD| Huntington’s Disease Society of America Home Comments http://hdsa.org/w8hat-is-hd/ How Common Is Huntington's Disease (HD)? | Huntington's NSW April 24, 2018www.huntingtonsnsw.org.au/information/hd-facts/how-common Huntington disease - Genetics Home Reference | U.S. National Library of Medicine National Institutes of Healthhttps://ghr.nlm.nih.gov/condition/huntington-disease#inheritance