Which of the following statements is correct regarding immunodeficiency disorders?

Explanation: The correct answer is c. Frequent and severe infections are common clinical manifestations of immunodeficiency disorders. The weakened immune system is unable to effectively defend against infections, leading to recurrent and severe infections.

Incorrect choices:

a. Severe allergic reactions are more characteristic of allergies or hypersensitivity disorders, not immunodeficiency disorders.

b. Chronic inflammation can be seen in various conditions, but it is not a specific clinical manifestation of immunodeficiency disorders.

d. Autoimmune diseases result from an overactive immune response attacking the body's own tissues, which is the opposite of immunodeficiency disorders where the immune system is weakened and unable to adequately protect against infections.

The correct answer is c. Ataxia-telangiectasia. Ataxia-telangiectasia is a rare genetic disorder that affects the cerebellum, causing poor muscle coordination (ataxia) and small, dilated blood vessels (telangiectasias). It also leads to defective T-cell function, making affected individuals more susceptible to infections.

Incorrect choices:

a. X-linked agammaglobulinemia (XLA) is a primary immunodeficiency disorder that primarily affects B-cell function, leading to a lack of mature B cells and low levels of immunoglobulins, but does not involve defective T-cell function.

b. Selective immunoglobulin A (IgA) deficiency is characterized by a deficiency of IgA, but it does not typically lead to defective T-cell function.

d. DiGeorge syndrome is caused by a deletion on chromosome 22 and primarily affects the development of certain organs, including the thymus and parathyroid glands, resulting in T-cell deficiency. While it may lead to some B-cell abnormalities, defective T-cell function is the hallmark of this disorder.