Mucolipidosis Type IV Mutation Analysis

Test Code

90899

CPT Codes
81290

Physician Attestation of Informed Consent

This germline genetic test requires physician attestation that patient consent has been received if ordering medical facility is located in AK, DE, FL, GA, IA, MA, MN, NV, NJ, NY, OR, SD or VT or test is performed in MA.

Preferred Specimen

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

Minimum Volume

3 mL whole blood • 3 mL bone marrow • 10 mL amniotic fluid • 10 mg dissected chorionic villus biopsy

Other Acceptable Specimens

Bone marrow collected in EDTA (lavender-top) tube • 10 mL amniotic fluid collected in a 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 (preferred): 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 and bone marrow
Room temperature: 8 days
Refrigerated: 8 days
Frozen: Unacceptable

⁠⁠⁠⁠⁠⁠⁠Fetal specimens
Room temperature: 48 hours
Refrigerated: Unacceptable
Frozen: Unacceptable

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

Do not reject

Methodology
Polymerase Chain Reaction (PCR) • Next Generation Sequencing

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: 11-17 days

Reference Range

See Laboratory Report

Clinical Significance

Mucolipidosis IV (MLIV) is an autosomal recessive, lysosomal storage disease, characterized by psychomotor retardation, and ophthalmologic abnormalities that include corneal opacities and retinal degeneration. This disease occurs primarily in individuals of Ashkenazi-Jewish descent and has an estimated carrier frequency of 1 in 100 in this population. MLIV is caused by mutations in the mucolipin-1 (MCOLN1) gene on chromosome 19. The IVS3-2A>G and 511del6.4kb mutations account for approximately 95% of Ashkenazi-Jewish MLIV mutations. The residual risk for an individual of full Ashkenazi-Jewish heritage to be a carrier of a MLIV mutation, after testing negative for the IVS3-2A>G and 511del6.4kb mutations, is approximately 1 in 1980.

The two MLIV mutations listed above are detected by polymerase chain reaction (PCR) amplification of the appropriate regions of the MCOLN1 gene, allele- specific primer extension, and allelic discrimination using a fluorescent reporter molecule and color-coded microspheres. Since genetic variation and other technical problems can affect the accuracy of direct mutation testing, the results of this testing should always be interpreted in light of the appropriate clinical and familial data.

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.