RFX-5, MHCII promoter X box regulatory factor 5 deficiency

Defects in RFX5 are a cause of hereditary MHC class II deficiency, also known as Bare lymphocyte syndrome (BLS) or HLA class II-deficient combined immunodeficiency); a form of Severe combined immunodeficiency disease (SCID) transmitted autosomal recessive. RFX5 is linked with BLS complementation groups C. The disease is very rare; only approximately 70 patients from 57 unrelated families have been reported worldwide.

Alternative names


Bare lymphocyte syndrome (BLS)

RFX5 (complementation group C)


  • Combined B and T cell immunodeficiencies
    • Major histocompatibility complex class II deficiency


Autosomal recessive


#209920 Bare lymphocyte syndrome, type II

*601863 Regulatory factor X, 5; RFX5


Incidence is not known yet.