What is the definition of Immunodeficiency with Hyper IGM Type 1?
Hyper IgM syndrome is a type of primary immunodeficiency syndrome. Primary immunodeficiency occurs when part of a person’s immune system is missing or does not work correctly. The bodies of people with primary immunodeficiency can’t get rid of germs or protect themselves from new germs as well as they should. Primary immunodeficiencies are inherited, meaning they are passed down from parents to children.
Hyper IgM syndromes are characterized by normal or elevated serum immunoglobulin M levels with absence of immunoglobulin G, A, and E. Immunoglobulins are proteins found in the blood. Hyper IgM results in a susceptibility to bacterial infections and sometimes opportunistic infections. There are five different types of hyper IgM syndromes (types 1-5). The types are distinguished by the location of the gene mutation involved.
What are the alternative names for Immunodeficiency with Hyper IGM Type 1?
- X-linked hyper IgM syndrome
- Hyper IgM immunodeficiency, x-linked
- Hyper IgM syndrome
- Hyper IgM syndrome 1
What are the causes for Immunodeficiency with Hyper IGM Type 1?
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.
What are the symptoms for Immunodeficiency with Hyper IGM Type 1?
Symptoms and physical findings associated with hyper IgM syndrome usually become apparent in the first or second year of life. This condition may be characterized by recurrent pus-producing (pyogenic) bacterial infections of the upper and lower respiratory tract including the sinuses (sinusitis) and/or the lungs (pneumonitis or pneumonia); the middle ear (otitis media); the membrane that lines the eyelids and the white portions (sclera) of the eyes (conjunctivitis); the skin (pyoderma); and/or, in some cases, other areas.
Other signs of the disease include enlarged tonsils, liver, and spleen, chronic diarrhea, and an increased risk of unusual or “opportunistic” infections and non-Hodgkins lymphoma. Opportunistic infections are infections caused by microorganisms that usually do not cause disease in individuals with fully functioning immune systems (non-immunocompromised) or widespread (systemic) overwhelming disease by microorganisms that typically cause only localized, mild infections. In individuals with Hyper-IgM Syndrome, such opportunistic infections may include those caused by Pneumocystis carinii, a microorganism that causes a form of pneumonia, or Cryptosporidium, a single-celled parasite (protozoa) that can cause infections of the intestinal tract.
In addition, individuals with Hyper-IgM Syndrome are prone to certain autoimmune disorders affecting particular elements of the blood. Autoimmune attacks on red blood cells lead to anemia, while autoimmune destruction of infection-fighting neutrophils further increases the risk of infection.
The range and severity of symptoms and physical features associated with this disorder may vary from case to case.
What are the current treatments for Immunodeficiency with Hyper IGM Type 1?
The cornerstone of treatment for individuals with hyper IgM syndrome is regular injections of intravenous immunogloblulin (IVIG). This treatment not only supplies missing IgG antibodies, but also prompts a drop in IgM antibodies. Patients with neutropenia can take granulocyte colony-stimulating factor (G-CSF). Antibiotics may also be prescribed to prevent the respiratory infection, pneumocystis carinii pneumonia.
Most children with hyper-IgM syndrome respond well to treatment, become symptom-free and resume normal growth.