Final answer:
Hyper-IgM syndrome is a primary immunodeficiency disorder characterized by a deficiency in the production of IgM antibodies and an inability to switch to other classes of antibodies. It involves defects in the CD40 ligand gene, resulting in weakened immune response and increased susceptibility to infections. Lab findings include low levels of IgG, IgA, and IgE antibodies.
Step-by-step explanation:
Hyper-IgM syndrome is a primary immunodeficiency disorder characterized by a deficiency in the production of IgM antibodies and an inability to switch from IgM to other classes of antibodies (such as IgG, IgA, and IgE). This results in a weakened immune response and an increased susceptibility to infections.
The pathophysiology of Hyper-IgM syndrome involves defects in the genes responsible for the production of a protein called CD40 ligand, which is essential for the activation of B cells and the production of class-switched antibodies. Lab findings in Hyper-IgM syndrome include low levels of IgG, IgA, and IgE antibodies, while IgM levels are often elevated.
In addition to the lab findings, patients with Hyper-IgM syndrome may experience recurrent bacterial and viral infections, particularly of the upper and lower respiratory tract.