Relevance of biallelic versus monoallelic TNFRSF13B mutations in distinguishing disease-causing from risk-increasing TNFRSF13B variants in antibody deficiency syndromes.

TNFRSF13B encodes transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), a B cell- specific tumor necrosis factor (TNF) receptor superfamily member. Both biallelic and monoallelic TNFRSF13B mutations were identified in patients with common variable immunodeficiency disorders. The genetic complexity and variable clinical presentation of TACI deficiency prompted us to evaluate the genetic, immunologic, and clinical condition in 50 individuals with TNFRSF13B alterations, following screening of 564 unrelated patients with hypogammaglobulinemia.

Screening of functional and positional candidate genes in families with common variable immunodeficiency.

Background: Common variable immunodeficiency (CVID) comprises a heterogeneous group of primary antibody deficiencies with complex clinical and immunological phenotypes. The recent discovery that some CVID patients show monogenic defects in the genes encoding ICOS, TACI or CD19 prompted us to investigate several functional candidate genes in individuals with CVID.

Results: The exonic, protein coding regions of the genes encoding: APRIL, BCMA, IL10, IL10Ralpha, IL10Rbeta, IL21, IL21R, and CCL18, were analyzed primarily in familial CVID cases, who showed evidence of genetic linkage to the respective candidate gene loci and CVID families with a recessive pattern of inheritance.

Disseminated cryptosporidium infection in an infant with hyper-IgM syndrome caused by CD40 deficiency.

We report the case of an infant with severe respiratory infections, chronic diarrhea, failure to thrive, and disseminated Cryptosporidium parvum infection. Laboratory investigations disclosed a diagnosis of hyper-IgM syndrome caused by CD40 deficiency.

Mutations of the X-linked lymphoproliferative disease gene SH2D1A mimicking common variable immunodeficiency.

Unlabelled: Common variable immunodeficiency (CVID) and X-linked lymphoproliferative (XLP) disease are two immunodeficiencies that may share a similar immunological phenotype making differential diagnosis difficult. We report two patients initially diagnosed as affected with CVID who, using molecular analysis, have been subsequently found to be affected with XLP disease. Distinguishing between these two diseases is essential since they have different prognosis, treatment and genetic counselling.