Cernunnos deficiency associated with BCG adenitis and autoimmunity: First case from the national Iranian registry and review of the literature

Non-homologous end joining (NHEJ) is a pathway that repairs double-strand breaks (DSB) in DNA and plays a vital role in V(D)J recombination of immunoglobulin genes. Cernunnos is a DNA repair factor that is involved in nonhomologous end-joining (NHEJ) process. Impairment in Cernunnos leads to a genetic disease characterized by neural disorders, immunodeficiency and increased radiosensitivity. We herein describe a severe combined immunodeficiency (SCID) patient with T- B+ phenotype who had a mutation in Cernunnos gene and manifested recurrent infections, microcephaly and growth retardation with hypogammaglobulinemia. Further-more, our patient was associated with BCG adenitis and autoimmunity that less is observed in patients with Cernunnos deficiency. In contrast to previous reported Cernunnos-deficient patients, our patient had normal B-cell number along with normal IgA and IgM, suggesting a leaky form of the Cemunnos deficiency due to residual count of B cells in our patient. Cemunnos deficiency should be considered in children with recurrent bacterial infections, microcephaly and growth retardation, in spite of having normal B-cell as well as normal IgM and IgA level. (C) 2017 Published by Elsevier Inc.