Hyper IgM Syndromes
Hyper IgM syndromes are a group of rare disorders in which the immune system does not function properly. They are classified as rare primary immunodeficiency disorders, which are a group of disorders characterized by irregularities in the cell development and/or cell maturation process of the immune system. The immune system is divided into several components, the combined actions of which are responsible for defending the body against different infectious agents.
Reference: Medline Plus