Job’s syndrome is the following type of immuno deficiency disease –
**Core Concept**
Job's syndrome, also known as Hyper-IgE syndrome, is a rare primary immunodeficiency disorder characterized by recurrent cutaneous and pulmonary infections, elevated levels of IgE, and distinctive skin and dental features. This condition is caused by mutations in the STAT3 gene, leading to impaired T-cell function and aberrant immune response.
**Why the Correct Answer is Right**
The correct answer is related to the underlying pathophysiology of Job's syndrome. Patients with Job's syndrome exhibit impaired T-cell function due to the STAT3 mutation, which affects the activation of T-cells and their ability to coordinate an effective immune response. This leads to the observed increased susceptibility to infections, particularly those caused by Staphylococcus aureus.
**Why Each Wrong Option is Incorrect**
**Option A:** Job's syndrome is a type of Combined Immunodeficiency (CID). This is incorrect because Job's syndrome is primarily a disorder of T-cell function, rather than a combined defect affecting multiple immune cell types.
**Option B:** Job's syndrome is characterized by low levels of IgG and IgA. This is incorrect because patients with Job's syndrome typically have normal or elevated levels of IgG and IgA, but significantly elevated levels of IgE.
**Option C:** Job's syndrome is caused by a mutation in the BTK gene. This is incorrect because Job's syndrome is caused by a mutation in the STAT3 gene, which affects T-cell function and signal transduction.
**Clinical Pearl / High-Yield Fact**
The distinctive skin features of Job's syndrome include eczema and characteristic facial features such as a prominent forehead, prominent cheeks, and a long face. These features, combined with the elevated IgE levels and recurrent infections, can help guide diagnosis.
**Correct Answer: D.**