Primary Open Angle Glaucoma via the MYOC Gene
Summary and Pricing 
Test Method
Exome Sequencing with CNV Detection
| Test Code | Test Copy Genes | Test CPT Code | Gene CPT Codes Copy CPT Code | Base Price | |
|---|---|---|---|---|---|
| 11501 | MYOC | 81479 | 81479,81479 | $990 | Order Options and Pricing |
Pricing Comments
Our favored testing approach is exome based NextGen sequencing with CNV analysis. This will allow cost effective reflexing to PGxome or other exome based tests. However, if full gene Sanger sequencing is desired for STAT turnaround time, insurance, or other reasons, please see link below for Test Code, pricing, and turnaround time information. If the Sanger option is selected, CNV detection may be ordered through Test #600.
An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.
Click here for costs to reflex to whole PGxome (if original test is on PGxome Sequencing platform).
Click here for costs to reflex to whole PGnome (if original test is on PGnome Sequencing platform).
The Sanger Sequencing method for this test is NY State approved.
For Sanger Sequencing click here.Turnaround Time
3 weeks on average for standard orders or 2 weeks on average for STAT orders.
Please note: Once the testing process begins, an Estimated Report Date (ERD) range will be displayed in the portal. This is the most accurate prediction of when your report will be complete and may differ from the average TAT published on our website. About 85% of our tests will be reported within or before the ERD range. We will notify you of significant delays or holds which will impact the ERD. Learn more about turnaround times here.
Targeted Testing
For ordering sequencing of targeted known variants, go to our Targeted Variants page.
Clinical Features and Genetics
Clinical Features
Glaucoma (GLC) is the second leading cause of irreversible blindness in developed countries. Primary Open angle glaucoma (POAG) is the most common form of glaucoma, defined as slowly progressive atrophy of the optic nerve and peripheral vision loss. Often, affected patients are asymptomatic, and the trabecular meshwork appears completely normal on clinical examination. The age of POAG onset ranges from less than 10 years to over 70 years. The majority of cases have disease onset after 40 years of age (Alward et al. 1998; Quigley 1996; Wiggs et al. 1996). Early diagnosis in at-risk individuals is essential for optimal application of existing therapies (Stone et al. 1997; Campos-Mollo et al. 2007).
Genetics
POAG is a relatively common, genetically heterogeneous disorder. MYOC (previously known as TIGR, trabecular meshwork-induced glucocorticoid response protein), was been mapped to human chromosome 1q21-q31 (hence also named GLC1A, first discovered gene on chromosome 1 that is associated with GLC). Mutations in MYOC can be responsible for both juvenile (autosomal recessive) and late-onset POAG (autosomal dominant) (Alward et al. 1998). MYOC mRNA is abundantly expressed in the ciliary rootlet and basal body of the connecting cilium of photoreceptor cells, iris, heart and skeletal muscle (Ortego et al. 1997; Kubota et al. 1997). MYOC encoded Myocilin contains a leucine zipper-like motif that is similar to that seen in kinectin and other cytoskeletal proteins, which suggests that myocilin is a novel cytoskeletal protein and possibly involved in the morphogenesis of ciliated neuroepithelium such as photoreceptor cells (Kubota et al. 1997). Mutations in MYOC account for 2-4% of POAG patients (Alward 2000). Over 130 causative MYOC mutations have been reported. The majority are missense mutations. Also, the great majority of reported mutations (over 90%) are located in the carboxy-terminus olfactomedin-homology (Olf) domain (Exon 3), which indicates this domain is important for Myocilin function (Gobeil et al. 2006; Rozsa et al. 1998).
Clinical Sensitivity - Sequencing with CNV PGxome
MYOC mutations account for 2-4% of POAG patients (Gobeil et al. 2006). The majority of MYOC mutations are missense (Human Gene Mutation Database), which are detectable by sequencing.
Testing Strategy
This test provides full coverage of all coding exons of the MYOC gene plus 10 bases of flanking noncoding DNA in all available transcripts along with other non-coding regions in which pathogenic variants have been identified at PreventionGenetics or reported elsewhere. We define full coverage as >20X NGS reads or Sanger sequencing. PGnome panels typically provide slightly increased coverage over the PGxome equivalent. PGnome sequencing panels have the added benefit of additional analysis and reporting of deep intronic regions (where applicable).
Dependent on the sequencing backbone selected for this testing, discounted reflex testing to any other similar backbone-based test is available (i.e., PGxome panel to whole PGxome; PGnome panel to whole PGnome).
Indications for Test
All patients with symptoms suggestive of open angle glaucoma are candidates.
All patients with symptoms suggestive of open angle glaucoma are candidates.
Gene
| Official Gene Symbol | OMIM ID |
|---|---|
| MYOC | 601652 |
| Inheritance | Abbreviation |
|---|---|
| Autosomal Dominant | AD |
| Autosomal Recessive | AR |
| X-Linked | XL |
| Mitochondrial | MT |
Disease
| Name | Inheritance | OMIM ID |
|---|---|---|
| Primary Open Angle Glaucoma Juvenile Onset 1 | AD | 137750 |
Citations
- Alward WL, Fingert JH, Coote MA, Johnson AT, Lerner SF, Junqua D, Durcan FJ, McCartney PJ, Mackey DA, Sheffield VC, Stone EM. 1998. Clinical features associated with mutations in the chromosome 1 open-angle glaucoma gene (GLC1A). New England Journal of Medicine 338: 1022–1027. PubMed ID: 9535666
- Alward WL. 2000. The genetics of open-angle glaucoma: the story of GLC1A and myocilin. Eye (Lond) 14 ( Pt 3B): 429–436. PubMed ID: 11026970
- Campos-Mollo E, Sánchez-Sánchez F, López-Garrido MP, López-Sánchez E, López-Martínez F, Escribano J. 2007. MYOC gene mutations in Spanish patients with autosomal dominant primary open-angle glaucoma: a founder effect in southeast Spain. Mol Vis 13: 1666–73. PubMed ID: 17893668
- Gobeil S, Letartre L, Raymond V. 2006. Functional analysis of the glaucoma-causing TIGR/myocilin protein: integrity of amino-terminal coiled-coil regions and olfactomedin homology domain is essential for extracellular adhesion and secretion. Exp. Eye Res. 82: 1017–1029. PubMed ID: 16466712
- Human Gene Mutation Database (Bio-base).
- Kubota R, Noda S, Wang Y, Minoshima S, Asakawa S, Kudoh J, Mashima Y, Oguchi Y, Shimizu N. 1997. A novel myosin-like protein (myocilin) expressed in the connecting cilium of the photoreceptor: molecular cloning, tissue expression, and chromosomal mapping. Genomics 41: 360–369. PubMed ID: 9169133
- Ortego J, Escribano J, Coca-Prados M. 1997. Cloning and characterization of subtracted cDNAs from a human ciliary body library encoding< i> TIGR, a protein involved in juvenile open angle glaucoma with homology to myosin and olfactomedin. FEBS letters 413: 349–353. PubMed ID: 9280311
- Quigley HA. 1996. Number of people with glaucoma worldwide. Br J Ophthalmol 80: 389–393. PubMed ID: 8695555
- Rozsa FW, Shimizu S, Lichter PR, Johnson AT, Othman MI, Scott K, Downs CA, Nguyen TD, Polansky J, Richards JE. 1998. GLC1A mutations point to regions of potential functional importance on the TIGR/MYOC protein. Mol Vis 4: 20. PubMed ID: 9772276
- Stone EM, Fingert JH, Alward WL, Nguyen TD, Polansky JR, Sunden SL, Nishimura D, Clark AF, Nystuen A, Nichols BE, Mackey DA, Ritch R, Kalenak JW, Craven ER, Sheffield VC. 1997. Identification of a gene that causes primary open angle glaucoma. Science 275: 668–670. PubMed ID: 9005853
- Wiggs JL, Damji KF, Haines JL, Pericak-Vance MA, Allingham RR. 1996. The distinction between juvenile and adult-onset primary open-angle glaucoma. American journal of human genetics 58: 243. PubMed ID: 8554064
Ordering/Specimens
Ordering Options
We offer several options when ordering sequencing tests. For more information on these options, see our Ordering Instructions page. To view available options, click on the Order Options button within the test description.
myPrevent - Online Ordering
- The test can be added to your online orders in the Summary and Pricing section.
- Once the test has been added log in to myPrevent to fill out an online requisition form.
- PGnome sequencing panels can be ordered via the myPrevent portal only at this time.
Requisition Form
- A completed requisition form must accompany all specimens.
- Billing information along with specimen and shipping instructions are within the requisition form.
- All testing must be ordered by a qualified healthcare provider.
For Requisition Forms, visit our Forms page
If ordering a Duo or Trio test, the proband and all comparator samples are required to initiate testing. If we do not receive all required samples for the test ordered within 21 days, we will convert the order to the most effective testing strategy with the samples available. Prior authorization and/or billing in place may be impacted by a change in test code.
Specimen Types
Specimen Requirements and Shipping Details
PGxome (Exome) Sequencing Panel
PGnome (Genome) Sequencing Panel
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ORDER OPTIONS
View Ordering Instructions1) Select Test Type
2) Select Additional Test Options
No Additional Test Options are available for this test.