CD40 ligand deficiency (DOID:0060022)
Alliance: disease page
Synonyms: HIGMX-1; X-linked hyper-IgM syndrome
Alt IDs: OMIM:308230
Definition: A combined T cell and B cell immunodeficiency that is a X-linked immunodeficiency with hyperimmunoglobulin M (XHIM) affecting isotype switching and is caused by the absence of CD40 ligand which is normally expressed on activated CD4+ T cells. Individuals with this mutation are unable to switch from IgM to IgG, IgA and IgE.