What is the primary cause of immunodeficiency disorders?

Explanation: The correct answer is c. Primary immunodeficiency disorders are typically present at birth or during early childhood and are caused by genetic defects that affect the function of the immune system. They are not acquired later in life due to environmental factors.

Incorrect choices:

a. Primary immunodeficiency disorders are not acquired later in life; they are usually genetic and present from birth.

b. Primary immunodeficiency disorders are characterized by a weakened or deficient immune response, not an overactive immune response.

d. Primary immunodeficiency disorders are often not easily treatable with antibiotics and antiviral medications because they result from genetic defects in the immune system.

Explanation: The correct answer is a. Severe combined immunodeficiency (SCID). SCID is a severe and rare primary immunodeficiency disorder characterized by the absence or severe impairment of both T and B cells, leading to a profound deficiency in cellular and humoral immunity.

Incorrect choices:

b. X-linked agammaglobulinemia (XLA) primarily affects B-cell function, resulting in a lack of mature B cells and low levels of immunoglobulins, but does not typically involve T-cell deficiency.

c. Wiskott-Aldrich syndrome affects platelet function and immune system regulation, but it is not characterized by a deficiency of both T and B cells.

d. Common variable immunodeficiency (CVID) is characterized by reduced levels of immunoglobulins, particularly IgG and IgA, but it does not typically lead to a complete deficiency of both T and B cells.