Cernunnos deficiency

Defects in NHEJ1, on chromosome 2q31, are a cause of T and B cell combined immune deficiency. This form of CID is characterized by microcephaly and immunodeficiency characterized by a profound T-and B-lymphocytopenia. Patients display an increased cellular sensitivity to ionizing radiation (IR), a defective V(D)J recombination and an impaired DNA-end ligation process.

Alternative names

Cernunnos XLFD

NEHJ deficiency, Cernunnos-XLF deficiency, Combined immunodeficiency (CID) associated with microcephaly and increased cellular sensitivity to IR


  • Combined B and T cell immunodeficiencies
    • Other


Autosomal recessive


Cross references

Phenotypically related immunodeficiencies

IDR factfile for DNA ligase IV deficiency

IDR factfile for Nijmegen-breakage syndrome


Incidence is not known yet.