Simplify the following text for a Grade 15 native English-speaking person.
Original: Immunodeficiency can either be the result of a genetic disease , such as severe combined immunodeficiency , or be produced by pharmaceuticals or an infection , such as the acquired immune deficiency syndrome ( AIDS ) that is caused by the retrovirus HIV .
Simplified: Immunodeficiency can either be the result of a genetic ( inherited ) disease , or an infection , such as the acquired immune deficiency syndrome ( AIDS ) , that is caused by the retrovirus HIV , or other causes .