22 Hard-To-Detect Illnesses, From The Commonplace To The Truly Bizarre

13. Huntington’s Disease

Spread genetically through the Huntington gene, Huntington’s disease is a neurological disorder that can cause hallucinations, paranoia, anxiety and involuntary limb movement. The scariest thing about the disease is that the inflicted generally do not show symptoms until their mid-30s. The average life span once the disease has been detected is 15-20 years.