Molecular test to confirm a diagnosis or assess carrier status for X-linked CGD.
- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics of chronic granulomatous disease (CGD):
A primary immunodeficiency disorder characterized by recurrent, severe bacterial and fungal infections of the skin, lymph nodes, liver, lungs, bones, or visceral organs. Dysregulated inflammatory responses result in granulomas.
Incidence: Approximately 1 in 250,000 births.
Inheritance: X-linked recessive for CYBB; de novo mutations in 10-20 percent of affected males.
Cause: Pathogenic mutations in the CYBB gene result in X-linked CGD. Autosomal recessive CGD may result from mutations in NCF1 (25 percent), CYBA (<5 percent), NCF2 (<5 percent) and NCF4 (very rare).
Clinical Sensitivity: 68 percent for CGD.
Methodology: Polymerase Chain Reaction/High Resolution Melt Analysis. Identified sequence variants are confirmed using targeted, bidirectional sequencing.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. Deep intronic mutations in CYBB are not detected in males or females. Large CYBB gene deletions/duplications will not be detected in carrier females. Breakpoints of large deletions/duplications will not be determined in males. Mutations in genes other than CYBB are not evaluated.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|2006363||CYBB for Chronic Granulomatous Disease|
- CGD mutation testing
- CYBB x-linked mutations