WOLF-HIRSCHHORN SYNDROME (4p-)
FISH ANALYSIS

The Kleberg Cytogenetics Laboratory offers a fluorescence in situ hybridization (FISH)-based assay for identifying the deletion of 4p16.3 associated with Wolf-Hirschhorn syndrome.

Clinical Features:

Individuals with Wolf-Hirschhorn syndrome have a specific pattern of dysmorphic facial features (“Greek warrior helmet appearance”), microcephaly, growth deficiency and mental retardation. Seizures, skeletal anomalies, congenital heart defects and hearing loss are also often seen in these patients.

Reasons for Referral:

Patients with clinical features suggestive of Wolf-Hirschhorn syndrome may be tested for a deletion of 4p16.3 by FISH simultaneously with high-resolution chromosomal analysis (if not previously performed). The majority of deletions are detectable with high-resolution chromosomal analysis. Prenatal diagnosis may be performed if an affected family member has been studied in our laboratory and has been shown to have a deletion detectable by FISH. Please call regarding all prenatal samples.

Testing Methodology:

FISH is the application of fluorescently labeled DNA molecules to metaphase chromosomes and interphase nuclei for the detection of chromosome abnormalities and alterations. It is a rapid, reliable and direct approach for identifying patients with microdeletions or microduplications. FISH analysis for deletion 4p16.3 is performed on metaphase chromosomes using a commercially available probe of the Wolf-Hirschhorn critical region (WHCR). The presence of one hybridization signal indicates a deletion. The WHCR probe will detect greater than 95% of patients with this microdeletion syndrome (Battaglia et al., 2002).

Specimen Requirements:

Whole blood in sodium heparin (green-top) tubes:
Newborn (< 3 months): Minimum 0.5 -2.0 CC
Adult/Child: Minimum 3.0 -5.0 CC

Shipping and Handling:

All tubes must be labeled with the patient's testname and date of birth, and a completed requisition form must accompany each sample. If the laboratory is billing the patient's insurance, please enclose a copy of the insurance card. Ship specimens for overnight delivery at ambient temperature. Please notify the laboratory of incoming samples.

Turnaround Time:

7-10 days

CPT Codes and Prices:

88230, 88271, 88273, 88291

References:

1. Altherr, et al. (1997) Am. J. Med. Genet. 71: 47-53.
2. Battaglia, et al. (1999) Pediatrics 103: 830-836.
3. Battaglia, et al. (2002) Gene Reviews.

Forms:

>> Cytogenetics Requisition
>> Prenatal Requisition

Test Code:

8484