Parkinson's disease is a progressive disorder of the nervous system that affects your movement.
In the early stages of Parkinson's disease, your face may show little or no expression or your arms may not swing when you walk.
Huntington's disease is an inherited disease that causes certain nerve cells in the brain to waste away.
People are born with the defective gene, but symptoms usually don't appear until middle age.
Color blindness is not a form of blindness at all, but a deficiency in the way you see color.
Color blindness occurs when light-sensitive cells in the retina fail to respond appropriately to variations in wavelengths of light that enable people to see sertain colors.