Features include always present findings: Decreased class-switched memory B cell proportion, Decreased total B cell count, Recurrent bacterial infections, and Decreased circulating IgA concentration and others; and common findings: Decreased circulating total IgM. 21 total HPO annotations.

ICOS encodes inducible T cell costimulator (199 aa). Stimulatory receptor expressed in activated or antigen-experienced T-cells that plays an important role in the immune response. Highest expression in Spleen (3.4 TPM) and Lung (2.2 TPM).

Immunodeficiency, common variable, 1 is associated with mutations in the ICOS gene on chromosome 2.

The ICOS protein participates in ICOS gene:p-STAT3, Co-stimulation by ICOS, and Co-inhibition by CTLA4 pathways.

ICOS is classified as a druggable target (Druggable Genome and Serine Threonine Kinase categories) with score 34.8.

Genetic testing for ICOS is available. Testing is considered confirmatory for diagnosis.

Biomarker and diagnostic research for immunodeficiency, common variable, 1 has been reported in the published literature.

Phenotype severity distribution: 5 always present features, 1 common feature.

2 clinical trials registered. Interventions under study include other interventions. Research is primarily sponsored by academic and government institutions.

174 publications have been identified in PubMed for immunodeficiency, common variable, 1. Kisho has analyzed 56 by research type. Research spans Epidemiology / Natural History (29%), Review / Meta-Analysis (23%), and Basic Science / Preclinical (18%).