Can you please tell me genetics of sickle cell anemia?

Inherited disease.: Sickle cell disease is genetic and is present at birth. It is inherited when a child receives two sickle cell genes—one from each parent. This disease is more common in blacks (people of african heritage). Sickle cell trait occurs when one sickle cell gene (“s”) is inherited from one parent and one normal gene (“a”) from the other. Those with trait are "carriers" and are often asymptomatic.

Sickle cell disease: Occurs when both copies of their beta globin gene (one received from each parent) harbor a mutation in codon 6 that changes the encoded Amino Acid from glutamate to valine. Patients can't make normal hemoglobin consequently, and instead can only make hgbs. If you inherit one normal and one beta-s, you can make some normal (hgba) and some hgbs. The normal hgba limits sickling. This is sickle trait.