Hyper IgM, Immunodeficiency with hyper IgM type 2 (hyper-IgM Immunodeficiency With, type 2) - Gen AICDA.

Immunodeficiency with hyper IgM type 2 (HIGM2) is a rare disorder characterized by normal or elevated levels of serum IgM with absence of IgG, IgA and IgE, which results in a profound susceptibility to bacterial infections. The absence of switch recombination immunoglobulin class (CSR), lack of immunoglobulin somatic hypermutation, and hyperplastic lymph nodes caused by the presence of germinal centers: in individuals affected three abnormalities characteristic of the disease manifest giants.

In most cases, this disease occurs in childhood, although its diagnosis may be delayed. Affected individuals manifest mainly infections in high and low, gastrointestinal infections, infections of the central, arthritis and lymphoid hyperplasia nervous system airways. Some patients have autoimmune involvement such as hemolytic anemia, thrombocytopenia and hepatitis. These individuals have a severe deficiency of IgG and IgA, whereas IgM levels are normal or increased.

This process is due to mutations in the gene AICDA, located on the short arm of chromosome 12 (12p13). This gene encodes a deaminase RNA that is a member of the family of cytidine deaminase (AID). The protein is involved in somatic hypermutation, gene conversion and class switch recombination in B cells is required for several critical steps in terminal B cell differentiation required for effective antibody responses. They can also play a role in epigenetic regulation of gene expression through participation in DNA demethylation. Mutations in the gene AICDA, leading to a deficiency of the enzyme AID.

This disease is inherited in an autosomal recessive pattern, that is, both copies of the gene in every cell must have mutations for alteration is expressed. The parents of an individual with an autosomal recessive d Sexually transmitted diseases have a copy of the mutated gene, but usually show no signs and symptoms of the disease.

Tests performed in IVAMI: in IVAMI perform detection of mutations associated with immunodeficiency with hyper IgM type 2 by PCR amplification of complete exons AICDA gene, and subsequent sequencing.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).