immunodeficiency 26 immunodeficiency 26 immunodeficiency 26 is a rare genetic syndrome. it is characterised by absent circulating b and t cells and normal natural killer cells. immunodeficiency 26immunodeficiency 26 is inherited in an autosomal recessive pattern.specialtymedical genetics signs and symptoms the features of this condition include recurrent candidiasis and lower respiratory tract infections. genetics this condition is due to mutations in the dna-pkcs gene and is inheritable in an autosomal recessive fashion. the gene is located on the long arm of chromosome 8 (8q11.21) on the minus strand. it encodes a protein of 4128 amino acids with a predicted molecular weight of 469 kilodaltons. the encoded protein is a protein kinase that is activated by dna. this protein acts as a sensor for damaged dna. diagnosis diagnosis is made by examination of the circulating lymphocytes and gene sequencing. differential diagnosis ataxia telangectasia artemis deficiency lig4 syndrome nijmegen breakage syndrome severe combined immunodeficiency with cernunnos x-linked agammaglobulinemia management epidemiology this condition is rare. only two cases have been described up to 2017. history this condition was described in 2009 by van der burg et al.