1) Describe a disease/disorder caused by a misfolded enzyme or protein

1) Describe a disease/disorder caused by a misfolded enzyme or protein.

What are the characteristics of the disease/disorder? That is, what are the noticeable symptoms, who/what is mostly affected, is it fatal, etc.?
2)Describe the misfolded enzyme or protein that leads to the disease/disorder? What is its name? What is the normal function of the enzyme or protein (remember the structure/function theme)?
3)Is this disease/disorder inherited? Is there a genetic contribution to the misfolding of the enzyme or protein?