What are the two immunodeficiency diseases?

The two main types of immunodeficiency diseases are:

1) Primary Immunodeficiency Diseases (PID): These are caused by genetic defects that affect the development and function of the immune system. Examples include Severe Combined Immunodeficiency (SCID), X-linked Agammaglobulinemia, Wiskott-Aldrich Syndrome, and DiGeorge Syndrome.

2) Secondary Immunodeficiency Diseases: These are acquired immunodeficiencies that occur due to external factors such as infections (e.g. HIV/AIDS), certain medications, malnutrition, chronic diseases (e.g. diabetes, cancer), and aging.