Mutations in CHD7 in patients with CHARGE syndrome cause T–B + natural killer cell + severe combined immune deficiency and may cause Omenn-like syndrome

Abstract

SummaryMore than 11 genetic causes of severe combined immunodeficiency (SCID) have been identified, affecting development and/or function of T lymphocytes, and sometimes B lymphocytes and natural killer (NK) cells. Deletion of 22q11.2 is associated with immunodeficiency, although less than 1% of cases are associated with T-B + NK + SCID phenotype. Severe immunodeficiency with CHARGE syndrome has been noted only rarely Omenn syndrome is a rare autosomal recessive form of SCID with erythroderma, hepatosplenomegaly, lymphadenopathy and alopecia. Hypomorphic recombination activating genes 1 and 2 mutations were first described in patients with Omenn syndrome. More recently, defects in Artemis, RMRP, IL7Ra and common gamma chain genes have been described. We describe four patients with mutations in CHD7, who had clinical features of CHARGE syndrome and who had T-B + NK + SCID (two patients) or clinical features consistent with Omenn syndrome (two patients). Immunodeficiency in patients with DiGeorge syndrome is well recognized -CHARGE syndrome should now be added to the causes of T-B + NK + SCID, and mutations in the CHD7 gene may be associated with Omenn-like syndrome.

CHARGE syndrome: a review of the immunological aspects

“…For 23 of 26 (88%) patients, T-cell lymphopenia was concomitant with T-cell dysfunction. 14,17,18,20,[22][23][24][25][26][27][28][29][30][31]33,[35][36][37] In our collected cohort, B-and/or NK-cell numbers were reported in only 29 of 59 patients, and of these 29 patients, 1 had low B-cell numbers, 1 had high B-cell numbers, 1 had low NK-cells numbers and 3 had high NK-cell numbers. The reported B-and NK-cells numbers of other patients were normal.…”

“…The reported B-and NK-cells numbers of other patients were normal. 14,23,[26][27][28][34][35][36] Immunoglobulin levels were reported in 33 of 59 patients and in 20 of 36 patients with a proven variant in CHD7. Hypogammaglobulinaemia was reported in 20 of 33 (61%) patients and measured along with T-cell lymphopenia in 14 of 18 (78%) patients.…”

“…14,[16][17][18][19][20][21][22] Three patients had features resembling Omenn syndrome, a form of severe combined immune deficiency, characterized by autoimmune-like features and macular skin rash due to the formation of abnormal, autoreactive T cells. 18,23 Other severe presentations included a patient with recurrent oral candidiasis, recurrent severe infections, and septic shock due to colonization with multiresistant species of Pseudomonas aeruginosa, Stenotrophomonas maltophilia and Acinobacter (Janda et al, 22 Table 1B); another patient with severe general dermatitis and ulcers of the colon (Boudny et al, 24 Table 1B); and a patient with CHARGE association and T-cell deficiency with a chronic viral infection of the gut (Wood et al, 25 Table 1C). …”

“…T-cell lymphopenia in our collected cohort was associated with thymic aplasia or hypoplasia in 21 of 22 (95%) patients. [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] T-cell function by response on mitogens was available for 28 of 59 patients and of these 28 patients 24 (86%) had a low or absent response on mitogen. For 23 of 26 (88%) patients, T-cell lymphopenia was concomitant with T-cell dysfunction.…”

“…14,17,[22][23][24][25][26][27][28][29]35,36 Thirteen of 33 (39%) patients with known immunoglobulin levels had IgG deficiency and 2 of these patients had received immunoglobulin replacement therapy. 14,[16][17][18][22][23][24][25][26][27][28][29]38 Of these 13 patients with IgG deficiency, 6 had recurrent or chronic infections and 1 had absent specific antibody responses. 14,[16][17][18]22,24,25 Isolated immunoglobulin deficiencies were rarely reported in CHARGE syndrome.…”