T−B+ SCID is the most common type of SCID. It is most often caused by X-linked recessive mutations in IL2RG, which encodes the γ chain (γc) common to several cytokine receptors such as IL-2R, IL-4R, IL-7R, IL-9R, IL-15R, and IL-21R. T−B+ SCID has also been associated with autosomal recessive mutations in other autosomal genes. Mutations in these genes lead to defective signaling through the γc receptors, resulting in an absence of both T cells and NK cells. B cells are present at normal levels, but have impaired function.
T−B− SCID is caused by autosomal recessive mutations in several genes, some of which are necessary for antigen receptor rearrangement, RAG1, RAG2, and DCLRE1C (ARTEMIS). Defects in these genes lead to impaired development of both B and T cells, while NK-cell development is normal.
If the patient's phenotype is more well-defined as either SCID B+ or SCID B-, phenotype-specific panels are available.
- Fischer A et al, (2005), Immunol Rev 203:98-109.
- Buckley RH et al, (2004), Annu Rev Immunol 22:625-55.
- Leonard W et al, (2001), Nat Rev Immunol 1:200-8.
- Confirmation of a clinical diagnosis of Severe Combined Immunodeficiency (SCID) B+.
- Confirmation of a clinical diagnosis of Severe Combined Immunodeficiency (SCID) B-.
Analytical Sensitivity: ~99%.
Submit only 1 of the following specimen types
Type: Whole Blood
Specimen Requirements:In EDTA (purple top) tube:
Infants (<2 years): 2-3 ml
Children (>2 years): 3-5 ml
Older Children & Adults: 5-10 ml
Specimen Collection and Shipping: Ship sample at room temperature with overnight delivery.
Type: Isolated DNA
Specimen Requirements:In microtainer: 60 ug
Isolation using the QiagenTM Puregene kit for DNA extraction is recommended.
Specimen Collection and Shipping: Refrigerate until time of shipment in 100 ng/ul of TE buffer. Ship sample at room temperature with overnight delivery.
- Severe Combined Immunodeficiency (SCID) B-: Sequencing Panel
- Severe Combined Immunodeficiency (SCID) B+: Sequencing Panel
- Severe Combined Immunodeficiency (SCID) B+/B-: Deletion/Duplication Panel