Walker-Warburg Syndrome

Test Code

92051

CPT Codes
81400

Preferred Specimen

5 mL whole blood collected in an EDTA (lavender-top) tube, ACD (yellow-top) tube, or sodium heparin (green-top) tube

Minimum Volume

4 mL whole blood • 10 mL amniotic fluid • 10 mg CVS

Other Acceptable Specimens

10 mL amniotic fluid collected in sterile leak-proof container • Cultured cells collected in each (x2) sterile T-25 flasks, 75% confluent • 10 mg chorionic villi collected in a sterile tube filled with sterile culture media

Instructions

Do not hold specimen; forward to laboratory when specimen arrives.

Whole blood: Specimen stability is crucial. Store and ship room temperature immediately. Do not freeze.

For fetal testing:
1) Please call 1-866-GENE-INFO (1-866-436-3463) prior to submission;
2) Documentation of parental carrier status must be provided;
3) It is required that Maternal Cell Contamination Study, STR Analysis be ordered in conjunction with fetal testing. A separate tube of maternal blood (EDTA) is required for this test.

Amniotic fluid (acceptable): Normal collection procedure. Specimen stability is crucial. Store and ship at room temperature immediately. Do not refrigerate or freeze; forward to laboratory when sample arrives.
Amniocyte or Chorionic Villus (CVS) culture (acceptable): Two sterile T25 flasks, 75% confluent, filled with culture medium. Specimen stability is crucial. Store and ship at room temperature immediately. Do not refrigerate or freeze; forward to laboratory when cells arrive.
Dissected Chorionic Villus (CVS) biopsy (acceptable): 10-20 mg dissected chorionic villi collected in sterile tube, filled with sterile culture medium. Specimen stability is crucial. Store and ship at room temperature immediately. Do not refrigerate or freeze; forward to laboratory when sample arrives.

Transport Temperature

Room temperature

Specimen Stability

Whole blood
Room temperature: 14 days
Refrigerated: 8 days
Frozen: Unacceptable

All other specimens
Room temperature: 48 hours
Refrigerated: Unacceptable
Frozen: Unacceptable

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Do not reject

Methodology
PCR amplification of specific gene regions followed by nucleotide sequence analysis on a massively parallel sequencing platform

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 FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Set up: Mon, Sat; Report available: 10-16 days

Reference Range

See Laboratory Report

Clinical Significance

The Walker-Warburg syndrome test offers molecular detection of one pathogenic variant in the FKTN gene, F390fs (c.1167dupA), which accounts for greater than 99% of Ashkenazi-Jewish Walker-Warburg syndrome pathogenic variants.

Walker-Warburg syndrome is an autosomal recessive multi-system disorder which affects the development of the brain, muscles, and eyes. Clinical features include significant intellectual disability, increasing hyptotonia, visual impairment, and early death.

Performing Laboratory

Quest Diagnostics Nichols Institute-San Juan Capistrano, CA

33608 Ortega Highway

San Juan Capistrano, CA 92675-2042

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.