True or false: An inherited defect in immune response is known as a primary immunodeficiency disease.

The statement is true because primary immunodeficiency diseases are characterized by defects in the immune system that are genetically inherited. These conditions are present at birth and result from intrinsic defects in immune cells or their functions. Examples include Severe Combined Immunodeficiency (SCID) and X-Linked Agammaglobulinemia (XLA). These conditions lead to an increased susceptibility to infections due to the body’s inability to mount an effective immune response.

In contrast, secondary immunodeficiency diseases arise from external factors, such as infections (like HIV), malnutrition, or medications that suppress the immune system. This distinction highlights why the term "primary immunodeficiency" specifically refers to those defects that are genetically inherited, affirming the accuracy of the true answer.