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Thrombocytopenia via the PTPRJ Gene

Summary and Pricing

Test Method

Exome Sequencing with CNV Detection
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
12643 PTPRJ 81479 81479,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
12643PTPRJ81479 81479,81479 $890 Order Options and Pricing

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 backbone).

Click here for costs to reflex to whole PGnome (if original test is on PGnome Sequencing backbone).

Turnaround Time

18 days on average for standard orders or 13 days 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.

EMAIL CONTACTS

Genetic Counselors

Geneticist

  • Siwu Peng, PhD

Clinical Features and Genetics

Clinical Features

Inherited thrombocytopenias (IT) comprise a heterogeneous group of disorders characterized by platelet counts below the lower limit of normal: 150,000/µL (150 x 109/L) in adults. Bleeding manifestations of thrombocytopenia range from mild to severe and may include excessive bruising (purpura), petechiae, prolonged bleeding from cuts or from surgical procedures, spontaneous nose bleeds, and in women, heavy menstrual flows. About half of ITs are syndromic disorders characterized by other physical and neurological anomalies, or immunodeficiencies (Balduini et al. 2013. PubMed ID: 23397552). Over 30 genes are known to be associated with ITs. Pathogenic variants in known genes are found in only about 50% of cases (Kunishima and Saito. 2006. PubMed ID: 16169642; Noris and Pecci. 2017. PubMed ID: 29222283). Noris and Pecci divide ITs into three groups: forms characterized by only platelet deficiencies, syndromic ITs with additional congenital defects, and ITs associated with increased risk of developing additional disease such as myelodysplastic syndrome (MDS) and acute leukemia (AL). For additional information regarding inherited hematologic malignancies, see Churpek et al. 2013. PubMed ID: 22691122; Furutani and Shimamura. 2017. PubMed ID: 28297620.

It is important to distinguish ITs from immune/idiopathic thrombocytopenias (ITP) in order to inform clinical management and identify potential at risk family members. The severity of ITs varies and disease may manifest within a few weeks of birth, or in patients with milder forms of IT symptoms may not appear until late adulthood. Given the genotypic and phenotypic heterogeneity found in IT patients, simultaneous genetic testing for a large subset of IT-related genes may provide the most efficient approach for establishing an accurate and timely diagnosis.

Genetics

The list of genes associated with inherited thrombocytopenias continues to grow. Pathogenic variants in PTPRJ are associated with autosomal recessive inherited thrombocytopenia. Two siblings with congenital microthrombocytopenia were recently reported to have compound heterozygous loss of function variants in PTPRJ; each parent carried one of the variants (Marconi et al. 2019. PubMed ID: 30591527). The disease presented as nonsyndromic thrombocytopenia with mild to moderate bleeding tendencies, small platelets, and impaired megakaryocyte maturation and platelet formation. The patients showed a severe depletion of PTPRJ protein in blood cells and PTPRJ protein levels in the carrier parents were decreased by ~ 50%. To date, these are the only patients reported to have PTPRJ-related thrombocytopenia.

PTPRJ (also known as CD148) is a receptor-type protein tyrosine phosphatase expressed in megakaryocytes. PTPRJ is a master regulator of Src family kinases which are essential for platelet activation and clotting (Senis. 2013. PubMed ID: 24015866). Consistent with the human phenotype, knockdown studies of the ptprja protein in zebrafish (homolog of human PTPRJ) showed a decrease in proplatelet formation (Marconi et al. 2019. PubMed ID: 30591527). PTPRJ has been cited as a conditional gene for growth of human tissue culture cells (Online Gene Essentiality, ogee.medgenius.info).

Clinical Sensitivity - Sequencing with CNV PGxome

Roughly half of inherited thrombocytopenias are not yet characterized (Balduini et al. 2013. 23397552). Pathogenic variants in PTPRJ are a rare cause of inherited thrombocytopenias as only two siblings have been identified to date with PTPRJ-related inherited thrombocytopenia (Marconi et al. 2019. PubMed ID: 30591527).

Testing Strategy

This test is performed using Next-Gen sequencing with additional Sanger sequencing as necessary.

This test provides full coverage of all coding exons of the PTPRJ 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 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

Patients with bleeding diatheses and a family history of thrombocytopenia who may or may not have other symptoms including immunodeficiencies, and physical or neurological anomalies. Targeted testing is indicated for family members of patients who have known pathogenic variants in PTPRJ. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in PTPRJ.

Gene

Official Gene Symbol OMIM ID
PTPRJ 600925
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Familial Colorectal Cancer 114500

Related Tests

Name
Thrombocytopenia Panel
Thrombocytopenia Panel - Expanded

Citations

  • Balduini et al. 2013. PubMed ID: 23397552
  • Churpek et al. 2013. PubMed ID: 22691122
  • Furutani and Shimamura. 2017. PubMed ID: 28297620
  • Kunishima and Saito. 2006. PubMed ID: 16169642
  • Marconi et al. 2019. PubMed ID: 30591527
  • Noris and Pecci. 2017. PubMed ID: 29222283
  • Online Gene Essentiality (OGEE).
  • Senis. 2013. PubMed ID: 24015866

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


Specimen Types

Specimen Requirements and Shipping Details

PGxome (Exome) Sequencing Panel

PGnome (Genome) Sequencing Panel

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ORDER OPTIONS

View Ordering Instructions

1) Select Test Method (Backbone)


1) Select Test Type


2) Select Additional Test Options

STAT and Prenatal Test Options are not available with Patient Plus.

No Additional Test Options are available for this test.

Note: acceptable specimen types are whole blood and DNA from whole blood only.
Total Price: $
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