Severe Combined Immunodeficiency (SCID) B+/B-: Deletion/Duplication Panel

Condition Description

Severe combined immunodeficiency (SCID) represents a group of rare, sometimes fatal, congenital disorders characterized by little or no immune response. The defining feature of SCID, commonly known as \"bubble boy\" disease, is a defect in the specialized white blood cells (B- and T-lymphocytes) that defend us from infection by viruses, bacteria, and fungi. Without a functional immune system, SCID patients are susceptible to recurrent infections such as pneumonia, meningitis, and chicken pox, and can die before the first year of life. SCID occurs with an estimated incidence of 1 in 75,000 births and is considered a pediatric emergency because of the potentially lethal outcome of recurrent or persistent infections suffered by SCID patients. Several monogenic causes with different modes of inheritance have been identified for SCID. Depending on the underlying genetic defect, different primary phenotypes associated with SCID have been characterized. Genetic testing for SCID can allow distinction between the various forms of this syndrome. Knowledge of the defective gene may have implications for treatment and prognosis. This knowledge may also enable more effective genetic counseling, in addition to facilitating identification of asymptomatic carriers and timely initiation of treatment in affected descendants of carriers.

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.
  • OMIM.
  • GeneReviews.

Genes (21)

Your search may have returned a result for a gene alias. Click here for a full list of genes and their aliases.


This test is indicated for:
  • Confirmation of a clinical diagnosis of Severe Combined Immunodeficiency (SCID) B+.
  • Confirmation of a clinical diagnosis of Severe Combined Immunodeficiency (SCID) B-.


Deletion/Duplication Analysis: DNA isolated from peripheral blood is hybridized to a gene-targeted CGH array to detect deletions and duplications. The targeted CGH array has overlapping probes that cover the entire genomic region.


Deletion/Duplication Analysis: Detection is limited to duplications and deletions. The CGH array will not detect point or intronic mutations. Results of molecular analysis must be interpreted in the context of the patient\'s clinical and/or biochemical phenotype.

Specimen Requirements

Listed below are EGL's preferred sample criteria. For any questions, please call 470.378.2200 and ask to speak with a laboratory genetic counselor (
Submit only 1 of the following specimen types
Whole Blood (EDTA)

EDTA (Purple Top)
Infants and Young Children (<2 years of age): 2-3 ml
Children > 2 years of age to 10 years old: 3-5 ml
Older Children & Adults: 5-10 ml
Autopsy: 2-3 ml unclotted cord or cardiac blood
Collection and Shipping
Ship sample at room temperature for receipt at EGL within 72 hours of collection. Do not freeze.
DNA, Isolated

Isolation using the Perkin Elmer™Chemagen™ Chemagen™ Automated Extraction method or Qiagen™ Puregene kit for DNA extraction is recommended.
Collection and Shipping
Refrigerate until time of shipment in 100 ng/µL in TE buffer. Ship sample at room temperature with overnight delivery.
  • Severe Combined Immunodeficiency (SCID) B+/B-: Sequencing Panel
  • Severe Combined Immunodeficiency (SCID) B-: Sequencing Panel
  • Severe Combined Immunodeficiency (SCID) B+: Sequencing Panel

How to Order

Requisition Forms