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FISH, Wolf-Hirschhorn
Test Code14613
CPT Codes
88271,88273
Includes
If this test is ordered without routine G-band chromosome analysis, a tissue culture charge will be added at an additional charge (CPT code: 88230).
Note: If results are not possible, the test order may be canceled and replaced with a Cytogenetics Communication.
Note: If results are not possible, the test order may be canceled and replaced with a Cytogenetics Communication.
Preferred Specimen
3 mL whole blood collected in a sodium heparin (green-top) tube
Minimum Volume
1 mL
Other Acceptable Specimens
Whole blood collected in: Sodium heparin (royal blue-top) tube, or sodium heparin lead-free (tan-top) tube
Instructions
Clinical history and reason for referral are required with test order.
Specimen viability decreases during transit. Send specimen to testing laboratory for viability determination. Do not freeze. Do not reject.
Specimen viability decreases during transit. Send specimen to testing laboratory for viability determination. Do not freeze. Do not reject.
Transport Temperature
Room temperature
Specimen Stability
Room temperature: See instructions
Refrigerated: See instructions
Frozen: See instructions
Refrigerated: See instructions
Frozen: See instructions
Methodology
Fluorescence in situ Hybridization (FISH)
FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.
Setup Schedule
Set up: Mon-Sat; Report available: 14 days
Reference Range
See Laboratory Report
Clinical Significance
This fluorescence in situ hybridization (FISH) assay detects a partial deletion of the Wolf-Hirschhorn syndrome (WHS) critical region (WHSCR) in chromosome 4p16.3. The results of this test may aid in the diagnosis of WHS.
WHS is a rare chromosomal deletion disorder characterized by distinct craniofacial features ("Greek warrior helmet" appearance), prenatal and postnatal growth deficiency, microcephaly, seizure, hypotonia, and intellectual disability [1]. Patients with WHS may also have congenital malformations in the heart, kidney, genitourinary tract, and skeleton. The pathogenesis of WHS involves multiple genes, and the clinical severity generally correlates with deletion size. The deletions associated with WHS can be de novo (85%-90%) or inherited from parental balanced rearrangements (10%-15%) [1].
A heterozygous deletion of the WHSCR on chromosome 4p16.3 detected by a FISH test supports the diagnosis of WHS [2]. However, because the FISH test is a targeted deletion analysis, a negative result of the FISH test does not rule out other deletions associated with the WHS or other deletion syndromes with similar clinical features. Chromosomal microarray detects almost all deletions of the WHSCR and can define the size of the deletion, and thus is considered the preferred test for WHS [2].
The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. Zollino M, et al. Am J Med Genet C Semin Med Genet. 2008;148C(4):257-269.
2. National Organization for Rare Disorders. Wolf-Hirschhorn syndrome. Accessed May 8, 2023. https://rarediseases.org/rare-diseases/wolf-hirschhorn-syndrome/
WHS is a rare chromosomal deletion disorder characterized by distinct craniofacial features ("Greek warrior helmet" appearance), prenatal and postnatal growth deficiency, microcephaly, seizure, hypotonia, and intellectual disability [1]. Patients with WHS may also have congenital malformations in the heart, kidney, genitourinary tract, and skeleton. The pathogenesis of WHS involves multiple genes, and the clinical severity generally correlates with deletion size. The deletions associated with WHS can be de novo (85%-90%) or inherited from parental balanced rearrangements (10%-15%) [1].
A heterozygous deletion of the WHSCR on chromosome 4p16.3 detected by a FISH test supports the diagnosis of WHS [2]. However, because the FISH test is a targeted deletion analysis, a negative result of the FISH test does not rule out other deletions associated with the WHS or other deletion syndromes with similar clinical features. Chromosomal microarray detects almost all deletions of the WHSCR and can define the size of the deletion, and thus is considered the preferred test for WHS [2].
The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. Zollino M, et al. Am J Med Genet C Semin Med Genet. 2008;148C(4):257-269.
2. National Organization for Rare Disorders. Wolf-Hirschhorn syndrome. Accessed May 8, 2023. https://rarediseases.org/rare-diseases/wolf-hirschhorn-syndrome/
Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153
