Immunodeficiency 26 Explained

Immunodeficiency 26
Field:	Medical genetics

Immunodeficiency 26 is a rare genetic syndrome. It is characterised by absent circulating B and T cells and normal natural killer cells.

Signs and symptoms

The features of this condition include recurrent candidiasis and lower respiratory tract infections.^[1]

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

Epidemiology

This condition is rare. Only three cases have been described up to 2023.^[2]

History

This condition was described in 2009 by van der Burg et al.^[3]

Notes and References

1. Mathieu AL, Verronese E, Rice GI, Fouyssac F, Bertrand Y, Picard C, Chansel M, Walter JE, Notarangelo LD, Butte MJ, Nadeau KC, Csomos K, Chen DJ, Chen K, Delgado A, Rigal C, Bardin C, Schuetz C, Moshous D, Reumaux H, Plenat F, Phan A, Zabot MT, Balme B, Viel S, Bienvenu J, Cochat P, van der Burg M, Caux C, Kemp EH, Rouvet I, Malcus C, Méritet JF, Lim A, Crow YJ, Fabien N, Ménétrier-Caux C, De Villartay JP, Walzer T, Belot A (2015) PRKDC mutations associated with immunodeficiency, granuloma, and autoimmune regulator-dependent autoimmunity. J Allergy Clin Immunol 135(6):1578-1588.e5. doi: 10.1016/j.jaci.2015.01.040.
2. Woodbine L, Neal JA, Sasi, N-K, Shimada M, Deem K, Coleman H, Dobyns WB, Ogi T, Meek K, Davies EG, Jeggo PA (2013) PRKDC mutations in a SCID patient with profound neurological abnormalities. J Clin Invest 123: 2969-2980
3. van der Burg M, Ijspeert H, Verkaik NS, Turul T, Wiegant WW, Morotomi-Yano K, Mari, P-O, Tezcan I, Chen, DJ, Zdzienicka MZ, van Dongen JJM, van Gent DC (2009) A DNA-PKCS mutation in a radiosensitive T-B- SCID patient inhibits Artemis activation and nonhomologous end-joining. J Clin Invest 119: 91-98