Which of the following clinical manifestations is commonly seen in individuals with immunodeficiency disorders?

Explanation: The correct answer is c. Failure to thrive. SCID is a severe form of immunodeficiency that affects multiple components of the immune system, leading to recurrent and severe infections and failure to thrive in affected infants.

Incorrect choices:

a. Recurrent ear infections are more commonly seen in other types of immunodeficiency disorders, such as selective IgA deficiency.

b. Chronic fatigue and lethargy may be seen in various medical conditions but are not specific to SCID.

d. Persistent joint pain is not a characteristic symptom of SCID. It may be associated with other autoimmune or inflammatory conditions.

Explanation: The correct answer is b. Genetic or inherited defects. Immunodeficiency disorders are primarily caused by genetic mutations or defects that result in a weakened or impaired immune system.

Incorrect choices:

a. While environmental factors can contribute to the development of secondary immunodeficiency disorders, they are not the primary cause of most immunodeficiency disorders.

c. Autoimmune reactions are not the primary cause of immunodeficiency disorders. Autoimmune disorders involve the immune system attacking the body's own tissues, not a deficiency in the immune system.

d. Excessive production of white blood cells is not the primary cause of immunodeficiency disorders. In fact, immunodeficiency disorders are characterized by a deficiency or impairment of white blood cells, which are essential components of the immune system.