The X-linked hyper-IgM (XHIGM) syndrome is an uncommon primary immunodeficiency disease caused by mutations in the gene for CD40 ligand and characterized by normal or elevated serum IgM, reduced levels of IgG and IgA, and defective T-cell function.

Synopsis

 opportunistic infections

• pneumonia
• upper respiratory infections
  • sinusitis
  • recurrent otitis

• recurrent/protracted diarrhea
• central nervous system infections (14%),
• systemic sepsis
• osteomyelitis

 encapsulated bacteria
 P. carinii
 Herpes virus family (including cytomegalovirus)
 Cryptosporidium

• Cryptosporidium-associated sclerosing cholangitis

 Cryptococcus
 Candida
 Histoplasma
 Bartonella.

Etiology

 mutations in the gene encoding CD40 ligand