What causes Immunodeficiency with hyper IgM type 1 ?
What causes hyper IgM syndrome? A flawed gene (or genes) in T-cells (a type of white blood cell that is part of the immune system and helps the body fight diseases or harmful substances) is responsible for hyper IgM syndrome. The faulty T-cells do not give B-cells a signal they need to switch from making IgM to IgA and IgG. Most cases (approximately 70%) of hyper-IgM syndrome are linked to a recessive mutation on the X chromosome. These cases are inherited as an X-linked recessive genetic trait. Because males do not have a second, healthy, X-chromosome to offset the disease, boys far out number girls with this disease. A small number of cases of hyper IgM syndrome have been attributed to autosomal recessive and autosomal dominant genetic inheritance. In addition, a rare acquired form of the disorder has been described in the medical literature.