GeneDx :: Tests :: Velocardiofacial Syndrome and DiGeorge Syndrome

301-519-2100 • FAX 301-519-2892 • 207 PERRY PARKWAY GAITHERSBURG, MD 20877

Velocardiofacial Syndrome and DiGeorge Syndrome

TBX1 (T-Box 1)

The majority (96%) of VCFS/DGS is caused by a genomic microdeletion on chromosome 22q11.2, typically detected by fluorescence in situ hybridization (FISH) using the TUPLE1 (HIRA) probe. GeneDx offers FISH analysis, or FISHonChip analysis, both are reliable and sensitive assays for detecting a VCFS/DGS deletion.

The remaining 5% of patients have a smaller, atypical 22q11.2 deletion, a chromosomal rearrangement involving 22q11.2, or mutations in the TBX1 gene. For those VCFS/DGS patients without the classic 3-Mb deletion, GeneDx performs bi-directional sequence analysis of the coding region and splice sites of the TBX1 gene (exons 1-9).

In appropriate cases, if TBX1 sequencing is negative and FISH testing using the TUPLE1 (HIRA) probe is negative, GenomeDx genome-wide array CGH is available to detect atypical deletions and duplications in the 22q11.2 region.

FISHonChip/GenomeDx analysis for detection of a 22q11.2 microdeletion or TBX1 gene sequencing requires one tube of blood in EDTA (purple top tube).
FISH analysis for detection of a 22q11.2 microdeletion requires one tube of blood in heparin (green top tube).
Buccal brushes CANNOT be accepted for this test.

Information Sheet, including prices and CPT codes
Consent Document
Genetic Test Sample Submission Form (Test Requisition Form) including Payment Options

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