Relative CD4 lymphopenia and a skewed memory phenotype are the main immunologic abnormalities in a child with Omenn syndrome due to homozygous RAG1-C2633T hypomorphic mutation.

[omenn syndrome]

We report a child with Omenn syndrome (OS ) due to homozygous RAG 1 -C 2 633 T mutations who had an unusual clinical and immunological presentation . She had delayed onset of OS-associated clinical features , had cleared a number of potentially fatal pathogens including respiratory syncytial virus , parainfluenza-3 virus and rotavirus , and was thriving at diagnosis . Laboratory assessment showed normal T and B lymphocyte number and function . T -cell-receptor repertoire in the blood was relatively diverse and her primary immunologic abnormality was skewing of circulating T -cells to the memory phenotype . A compelling explanation for the perplexing combination in OS of atopic /autoimmune and immunologic features has proven elusive . Homozygous RAG 1 -C 2 633 T hypomorphic mutation may lead to significant residual immunity and a skewed memory phenotype . Our findings suggest that , in addition to host-genetic factors , environment , and /or pathogens , hypomorphic RAG mutations may differentially impact on V (D )J recombination activity and hence lead to a variable ability to sustain T and B cell lymphopoiesis . Importantly , this case emphasizes that such hypomorphic mutations may promote an attenuated phenotype , complicating the diagnosis of primary immunodeficiency (PID ).

Diseases
Validation

Diseases presenting "immunodeficiency" symptom

adrenal incidentaloma

allergic bronchopulmonary aspergillosis

cushing syndrome

dracunculiasis

hirschsprung disease

hodgkin lymphoma, classical

homocystinuria without methylmalonic aciduria

kabuki syndrome

legionellosis

malignant atrophic papulosis

oculocutaneous albinism

omenn syndrome

papillon-lefèvre syndrome

primary effusion lymphoma

primary hyperoxaluria type 1

pyomyositis

severe combined immunodeficiency

sneddon syndrome

werner syndrome

wiskott-aldrich syndrome

wolf-hirschhorn syndrome

x-linked adrenoleukodystrophy

This symptom has already been validated