The first case of autosomal recessive CADINS-like disease caused by novel compound heterozygous hypomorphic variants in CARD11.

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Presentation Time: 11:30 AM - 12:45 PM
Poster Board Number: B735
Abstract ID: 5377

Presenting Author:
Alison R Spratt , Research Assistant 1 at Uniformed Services Univ. of the Hlth. Sci., Henry M. Jackson Fndn. for the Advancement of Mil. Med.

Abstract:

CARD11 is a lymphocyte-specific scaffold protein connecting antigen receptor ligation to signaling governing lymphocyte proliferation and differentiation. We and others have shown that heterozygous, dominant negative (DN) CARD11 mutations disrupting T cell receptor (TCR)-induced NF-κB signaling cause severe atopy in humans, often with recurrent infections and humoral immune deficits. Here we describe a patient with a history of recurrent upper respiratory infections, recalcitrant atopic dermatitis and common variable immunodeficiency, carrying novel compound heterozygous CARD11 variants (G689E, R920L) in regions of the protein (PDZ and L4, respectively) not normally associated with deleterious mutations. By transfecting variant expression plasmids into CARD11-deficient Jurkat T cells harboring an NF-κB-driven GFP reporter, we found that G689E was mildly hypomorphic, whereas R920L was a complete loss-of-function mutation with negligible DN activity against wild-type CARD11. However, TCR-induced NF-κB activity was markedly reduced upon variant co-expression, strongly suggesting this patient represents the first autosomal recessive case of CARD11-associated Atopy with Dominant Interference of NF-κB Signaling (CADINS) disease. Additional experiments examining different amino acid substitutions at these residues highlight key biochemical interactions between the PDZ and L4 domains, with important implications for future CARD11 structure-function and clinical diagnostic studies.