Alpha-1 antitrypsin (AAT) deficiency is an inherited disease.
"Inherited" means it's passed from parents to children through
genes. Children who have AAT deficiency inherit two faulty AAT
genes, one from each parent. These genes tell cells in the body
how to make AAT proteins. In AAT deficiency, the AAT proteins
made in the liver aren't the right shape. Thus, they get stuck
in the liver cells. The proteins can't get to the organs in the
body that they protect, such as the lungs. Without the AAT
proteins protecting the organs, diseases can develop. The most
common faulty gene that can cause AAT deficiency is called PiZ.
If you inherit two PiZ genes (one from each parent), you'll have
AAT deficiency. If you inherit a PiZ gene from one parent and a
normal AAT gene from the other parent, you won't have AAT
deficiency. However, you might pass the PiZ gene to your
children. Even if you inherit two faulty AAT genes, you may not
have any related complications. You may never even realize that
you have AAT deficiency.