Gray Platelet Syndrome via the NBEAL2 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 | |
|---|---|---|---|---|---|
| 11507 | NBEAL2 | 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
Gray platelet syndrome (GPS; OMIM 139090) is characterized primarily by mild to severe bleeding tendency, and moderate thrombocytopenia with enlarged platelets that lack α-granules (Raccuglia, G. Am J Med 51: 818, 1971; Breton-Gorius et al. Am J Pathol 102: 10, 1981; Gunay-Aygun et al. Blood 116: 4990, 2010). Platelets appear gray in color in peripheral blood smears, which is attributed to a lack of platelet granules. Patients also have deficiencies in platelet α-granule proteins including von Willebrand factor, fibrinogen, platelet factor-4, and thrombospondin that are required for proper thrombosis. Other clinical and biochemical characteristics of GPS include platelet aggregation deficiencies in response to collagen and thrombin, epistaxis, splenomegaly, gray polymorphonuclear neutrophils, and myelofibrosis. GPS is a progressive disorder with symptoms first appearing in infancy or early childhood.
Genetics
Variants in the NBEAL2 gene (OMIM 614169) are the only known cause of GPS and are inherited in an autosomal recessive manner. Cases of GPS showing an autosomal dominant pattern of inheritance have been observed, suggesting genetic heterogeneity for GPS (Crowell and Eisner. Blood 40: 227, 1972; Chesney et al. Blood 43: 821, 1974). The NBEAL2 gene encodes a BEACH domain-containing protein that is thought to play a role in platelet α-granule biogenesis and trafficking (see Gunay-Aygun et al. Nat Genet. 43:732, 2011; and Kahr et al. Nat Genet. 43:738, 2011). Causative variants in NBEAL2 are primarily missense, but small and large deletions and splicing variants have also been identified (Albers et al. Nat Genet. 43: 735, 2011; Kahr et al. Nat Genet. 43:738, 2011; Gunay-Aygun et al. Nat Genet. 43:732, 2011). The severity of symptoms in GPS patients varies, even among family members, and does not correlate with the type or location of NBEAL2 variant (Gunay-Aygun et al. Nat Genet. 43:732, 2011).
Clinical Sensitivity - Sequencing with CNV PGxome
Sensitivity of this test is currently unknown.
Testing Strategy
This test provides full coverage of all coding exons of the NBEAL2 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
Individuals with bleeding diathesis, nosebleeds, and thrombocytopenia with enlarged, gray platelets. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in NBEAL2.
Individuals with bleeding diathesis, nosebleeds, and thrombocytopenia with enlarged, gray platelets. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in NBEAL2.
Gene
| Official Gene Symbol | OMIM ID |
|---|---|
| NBEAL2 | 614169 |
| Inheritance | Abbreviation |
|---|---|
| Autosomal Dominant | AD |
| Autosomal Recessive | AR |
| X-Linked | XL |
| Mitochondrial | MT |
Disease
| Name | Inheritance | OMIM ID |
|---|---|---|
| Gray Platelet Syndrome | AR | 139090 |
Citations
- Albers et al. Exome sequencing identifies NBEAL2 as the causative gene for gray platelet syndrome. Nat Genet 43(8):735-7, 2011. PubMed ID: 21765411
- Breton-Gorius et al. Defective alpha-granule production in megakaryocytes from gray platelet syndrome: ultrastructural studies of bone marrow cells and megakaryocytes growing in culture from blood precursors. Am J Pathol. 102(1):10-9, 1981. PubMed ID: 7468753
- Chesney et al. A syndrome of platelet-release abnormality and mild hemophilia. Blood. 43(6):821-30, 1974. PubMed ID: 4545510
- Crowell and Eisner. Familial association of thrombopathia and antihemophilic factor (AHF, factor VIII) deficiency. Blood. 40(2):227-33, 1972. PubMed ID: 4537881
- Gunay-Aygun et al. Gray platelet syndrome: natural history of a large patient cohort and locus assignment to chromosome 3p. Blood. 116(23):4990-5001, 2010. PubMed ID: 20709904
- Gunay-Aygun et al. NBEAL2 is mutated in gray platelet syndrome and is required for biogenesis of platelet α-granules. Nat Genet 43(8):732-4, 2011. PubMed ID: 21765412
- Kahr et al. Mutations in NBEAL2, encoding a BEACH protein, cause gray platelet syndrome. Nat Genet 43(8):738-40, 2011. PubMed ID: 21765413
- Raccuglia G. Gray platelet syndrome. A variety of qualitative platelet disorder. Am J Med. 51(6):818-28, 1971. PubMed ID: 5129551
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.