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

Minimum Volume
Whole blood: 3 mL
Amniotic fluid: 10 mL
Cultured amniotic fluid: 10 mL
chorionic villus: 10 mg

Other Acceptable Specimens
Whole blood collected in: ACD solution A or B (yellow-top), EDTA (royal blue-top), sodium heparin (green-top) or lithium heparin (green-top) • 20 mL amniotic fluid • 20 mL cultured amniocytes • 20 mg chorionic villus

Instructions
Whole blood (preferred): Normal phlebotomy procedure. Specimen stability is crucial. Store and ship room temperature immediately. Do not freeze. For prenatal diagnosis with a fetal specimen: 1) parents must be documented carriers of one of the mutations tested; 2) maternal blood or DNA must be available; 3) contact the laboratory genetic counselor before submission.

Amniotic fluid (acceptable): Normal collection procedure. Specimen stability is crucial. Store and ship room temperature immediately. Do not refrigerate or freeze.

Amniocyte culture (acceptable): Sterile T25 flask, filled with culture medium. Specimen stability is crucial. Store and ship room temperature immediately. Do not refrigerate or freeze.

Dissected chorionic villus (CVS) biopsy (acceptable): 10-20 mg dissected chorionic villi collected in sterile tube filled with sterile culture media. Specimen stability is crucial. Store and ship room temperature immediately. Do not refrigerate or freeze.
Forward cells to laboratory immediately.

Transport Temperature
Room temperature

Specimen Stability
Whole blood
Room temperature: 8 days
Refrigerated: 8 days
Frozen: Unacceptable

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

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 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: 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.

Performing Laboratory
Quest Diagnostics Nichols Inst San Juan Capistrano
33608 Ortega Highway
San Juan Capistrano, CA 92690-6130



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.