"Leaky" variants in RAG1 or RAG2 with residual protein function and T cell production can have a variable presentation, including Omenn syndrome, granulomatous disease, and/or autoimmunity.

OX40 deficiency is a rare immunodeficiency. CD4+ T cells appear to be dysfunctional in this disorder, whereas antibody production is still intact.

NIK deficiency is a rare immunodeficiency resulting in impaired function of T cells, B cells, and natural killer (NK) cells. Affected individuals are susceptible to a wide range of infections.

Variants in the gene that codes for a protein called nibrin cause Nijmegen breakage syndrome (NBS). Affected individuals are highly sensitive to the effects of sunlight and radiation, or any substance that can cause breaks in DNA.

Moesin deficiency is an X-linked immunodeficiency associated with lymphopenia, neutropenia, and recurrent bacterial infections.

MALT1 deficiency is a combined immunodeficiency that can cause severe eczema, recurrent bacterial and viral infections, inflammatory gastrointestinal disease, long bone fractures, and severe periodontal disease.

Individuals with ligase 1 deficiency have high sensitivity to sunlight, stunted growth, developmental delay, and a high predisposition for cancer.

Lung disease, immunodeficiency, and chromosome breakage syndrome (LICS) causes severe, early lung disease.

Autosomal recessive disorder due to deficiency of lymphocyte-specific protein-tyrosine kinase (Lck or p56lck), one of the proteins activated upon engagement of the TCR/CD3 complex. Depending on the mutation, individuals may present within the first year of life with variable features.