Condensed progeria description

Progeria is a rare and fatal disease.  It is caused by a small mutation in a protien called Lamin A.  It is very unusual to have more than one child in the same family  affected by this disease.  When a child is affected by progeria, they are not mentally affected at all, but physically they experience drastic change in appearance.  They age four times as fast then a normal funtioning person, and ultimately look like an elderly person even at a young age.