UNG deficiency

Defects in UNG are a cause of immunodeficiency with hyper-IgM type 5 syndrome (HIGM5). Hyper-IgM syndrome is a condition characterized by normal or increased serum IgM concentrations associated with low or absent serum IgG, IgA, and IgE concentrations. HIGM5 is associated with profound impairment in immunoglobulin (Ig) class-switch recombination (CSR) at a DNA precleavage step.

Alternative names


Hyper-IgM syndrome 5

Hyper-IgM syndrome, type 5

Uracil-DNA glycolase


  • Deficiencies predominantly affecting antibody production
    • Defects of class-switch recombination and somatic hypermutation (Hyper-IgM syndromes) affecting B cells


Autosomal recessive


#608106 Immunodeficiency with Hyper-IgM, type 5

*191525 Uracil-DNA glycosylase, UNG


Incidence is not known.