22q11.2 Deletion/Duplication, FISH, Varies

Casandra

Casandra Test Code MC99737Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID DD22FCPT Codes 88271, 88273, 88274, 88275, 88291

22q11.2 Deletion/Duplication, FISH, Varies

Clinical Use

Use

The 22q11.2 deletion/duplication test is utilized for establishing a diagnosis of 22q deletion or duplication syndromes. It is valuable in detecting cryptic rearrangements within the 22q11.2 or 22q11.3 regions that may not be evident through conventional chromosome studies. These syndromes often present with overlapping phenotypes, including growth deficiency, developmental delay, heart defects, and other facial anomalies. The test assists in confirming diagnoses for related conditions, such as DiGeorge syndrome and velocardiofacial syndrome, by targeting specific genetic alterations within these critical chromosomal regions.

Special Instructions

A reason for testing must be provided for this analysis to proceed effectively. While optional, submitting this information facilitates precise testing and interpretation. Additionally, this FISH test is not a substitute for comprehensive cytogenetic analysis. It is recommended to complement this test with additional cytogenetic assessments like chromosomal microarray or chromosome analysis to detect other chromosomal or structural anomalies.

Limitations

The 22q11.2 deletion/duplication test may not detect minuscule deletions within the specific region or very distal deletions on chromosome 22 at q13.3. It is primarily used as an adjunct test and is not FDA-approved. This method is ineffective for detecting low-level mosaicism. Users should be cautious of factors that could interfere with the analysis, such as the use of improper anticoagulants, excessive transport time, or exposure to temperature extremes, which might affect cell viability and the test's reliability.

Test Details

New York Approved