About Hyper IgM Syndrome
Hyper IgM Syndrome is a group of rare primary immunodeficiencies characterized by elevated or normal serum IgM with markedly reduced or absent IgG, IgA, and IgE, caused by defects in the molecular machinery required for B-cell class-switch recombination. The most common form is X-linked, caused by mutations in CD40LG encoding CD40 ligand, and predisposes patients to opportunistic infections including Pneumocystis jirovecii pneumonia and Cryptosporidium cholangiopathy. Hematopoietic stem cell transplantation is the only curative option currently available for CD40L deficiency.
Common Clinical Features
Clinical Trial Eligibility Tips
What to know before applying to Hyper IgM Syndrome trials.
Confirm the specific molecular defect (CD40LG, AID, UNG, or other) as gene therapy trials are mutation-specific and not interchangeable across HIGM subtypes
Active Cryptosporidium infection or established biliary cirrhosis may exclude from transplant conditioning trials — current liver function tests and imaging are essential
Neutropenia trials may co-enroll HIGM patients; document ANC nadir and G-CSF use history
Patient Resources
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