Hyper IgM Syndrome (HIGM) is a rare, primary immunodeficiency disorder characterized by a defect in the ability of B cells to undergo class switch recombination. This leads to an overproduction of Immunoglobulin M (IgM) and a deficiency in other immunoglobulin classes such as IgG, IgA, and IgE. The condition is usually identified in early childhood.
