DNA icon

Thrombocytopenia 4 via the CYCS 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
CYCS 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
10047CYCS81479 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.

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.


Genetic Counselors


  • 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, below 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.

CYCS-associated thrombocytopenia is a mild form of autosomal dominant inherited thrombocytopenia. Platelets are typically normal in size and morphology and range in number from 70-80/µL. Patients are not reported to have any obvious bleeding abnormalities or extra hematologic defects (Morison et al. 2008. PubMed ID: 18345000; De Rocco et al. 2014. PubMed ID: 24326104; Uchiyama et al. 2018. PubMed ID: 30051457).


Variants in CYCS show complete penetrance and account for only a small fraction of inherited thrombocytopenias. To date, only a handful of patients having one of only 4 CYCS gene variants, comprised by three missense variants and one small deletion, have been reported (Morison et al. 2008. PubMed ID: 18345000; De Rocco et al. 2014. PubMed ID: 24326104; Uchiyama et al. 2018. PubMed ID: 30051457; Johnson et al. 2016. PubMed ID: 27479822). Missense variants enhance the apoptotic activity of cytochrome c causing dysregulated megakaryopoiesis and ectopic release of platelets within bone marrow rather than into sinusoids which results in thrombocytopenia (Morison et al. 2008. PubMed ID: 18345000; De Rocco et al. 2014. PubMed ID: 24326104). CYCS encodes cytochrome c, a highly conserved protein that is found in the mitochondrial inner membrane and has roles in mitochondrial electron transport, antioxidant defense, and apoptosis.

Clinical Sensitivity - Sequencing with CNV PGxome

Over 30 genes are known to be associated with inherited thrombocytopenias. 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). Pathogenic variants in CYCS have been reported in few patients and are likely not a frequent cause of inherited thrombocytopenia (Kunishima et al. 2013. PubMed ID: 23434115).

Testing Strategy

Copy number variants (CNVs) are also detected from NGS data. We utilize a CNV-calling algorithm that compares mean read depth and distribution for each target in the test sample against multiple matched controls. Neighboring target read depth and distribution and zygosity of any variants within each target region are used to reinforce CNV calls. All CNVs are confirmed using another technology such as aCGH, MLPA, or PCR before they are reported.

This test provides full coverage of all coding exons of the CYCS gene plus coverage of 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

Patients with a personal or family history of low platelet counts with no other symptoms.


Official Gene Symbol OMIM ID
CYCS 123970
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Thrombocytopenia 4 AD 612004

Related Tests

Bleeding Disorders Panel
Hereditary Myelodysplastic Syndrome (MDS) / Acute Myeloid Leukemia (AML) Panel
Thrombocytopenia Panel


  • Balduini et al. 2013. PubMed ID: 23397552
  • Churpek et al. 2013. PubMed ID: 22691122
  • De Rocco et al. 2014 PubMed ID: 24326104
  • Furutani and Shimamura. 2017. PubMed ID: 28297620
  • Johnson et al. 2016 PubMed ID: 27479822
  • Kunishima and Saito. 2006. PubMed ID: 16169642
  • Kunishima et al. 2013. PubMed ID: 23434115
  • Morison et al. 2008. PubMed ID: 18345000
  • Noris and Pecci. 2017. PubMed ID: 29222283
  • Uchiyama et al. 2018. PubMed ID: 30051457


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

loading Loading... ×


An error has occurred while calculating the price. Please try again or contact us for assistance.

View Ordering Instructions

1) Select Test Method (Platform)

1) Select Test Type

2) Select Additional Test Options

No Additional Test Options are available for this test.

Note: acceptable specimen types are whole blood and DNA from whole blood only.
Total Price: loading
Patient Prompt Pay Price: loading
A patient prompt pay discount is available if payment is made by the patient and received prior to the time of reporting.
Show Patient Prompt Pay Price
Copy Text to Clipboard