Question

Describe the pathophysiology and lab findings in Hyper-IgM syndrome:

a) Pathophysiology: Defect in CD40 ligand leading to impaired class switching; Lab findings: Elevated IgM, low IgG/IgA, normal IgE
b) Pathophysiology: Defect in BTK gene leading to defective B cell signaling; Lab findings: Elevated IgG, low IgM/IgA, normal IgE
c) Pathophysiology: Defect in WAS gene leading to defective cytoskeletal regulation; Lab findings: Elevated IgE, low IgM/IgG/IgA
d) Pathophysiology: Defect in NEMO gene leading to impaired NF-kB signaling; Lab findings: Elevated IgA, low IgM/IgG, normal IgE

Answer 1

Hyper-IgM syndrome is a primary immunodeficiency disorder characterized by defects in different genes, resulting in impaired immune function. The lab findings vary depending on the specific genetic defect, but generally include elevated IgM levels and low levels of other immunoglobulins.

Step-by-step explanation:

Hyper-IgM syndrome is a primary immunodeficiency disorder that can be caused by different genetic defects, leading to impaired class switching and abnormal antibody production. In Hyper-IgM syndrome type 1, there is a defect in the CD40 ligand, resulting in impaired interaction between B cells and T cells, which is necessary for class switching. Lab findings in this type include elevated IgM levels and low IgG/IgA levels.

Hyper-IgM syndrome type 2 is caused by a defect in the BTK gene, which is involved in B cell signaling. This defect affects the maturation and differentiation of B cells, leading to a deficiency in immunoglobulins. Lab findings in this type include elevated IgG levels and low IgM/IgA levels.

Hyper-IgM syndrome type 3 is caused by a defect in the WAS gene, which is responsible for cytoskeletal regulation. This defect affects the migration and activation of immune cells, leading to abnormal immune responses. Lab findings in this type include elevated IgE levels and low IgM/IgG/IgA levels.

Hyper-IgM syndrome type 4 is caused by a defect in the NEMO gene, which is involved in NF-kB signaling. This defect affects the activation and function of immune cells, leading to immune dysregulation. Lab findings in this type include elevated IgA levels and low IgM/IgG levels.