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HelpTest Code GNMY9 MYH9-Related Disorders, MYH9 Gene, Next-Generation Sequencing, Varies
Ordering Guidance
This test is designed to evaluate MYH9-related disorders, including May-Hegglin disorder/anomaly and Sebastian syndrome, and to be utilized for genetic confirmation of a phenotypic diagnosis of an MYH9-related disorder.
If testing for hereditary platelet disorders using a larger panel is desired, a 70-gene platelet disorder panel is available; order GNPLT / Platelet Disorders, Comprehensive Gene Panel, Next-Generation Sequencing, Varies.
This test is not designed to evaluate for hereditary bleeding disorders. For patients with clinical suspicion of an inherited bleeding disorder, it is important to exclude plasmatic factor deficiencies (eg, von Willebrand disease, hemophilia, or other factor deficiencies) prior to considering an inherited platelet function defect. If bleeding is the indication for testing and testing for hereditary bleeding disorders is desired, bleeding panels are available. For more information see GNBLF / Bleeding Disorders, Focused Gene Panel, Next-Generation Sequencing, Varies or GNBLC / Bleeding Disorders, Comprehensive Gene Panel, Next-Generation Sequencing, Varies.
For assessment of hereditary platelet disorders that have ultrastructural abnormalities, such as gray platelet syndrome, order PTEM / Platelet Transmission Electron Microscopic Study, Whole Blood.
For assessment of hereditary platelet disorders due to quantitative surface glycoprotein deficiencies, order PLAFL / Platelet Glycoprotein Flow Platelet Surface Glycoprotein by Flow Cytometry, Blood.
Testing for the MYH9 gene as part of a customized panel is available. For more information see CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies.
Targeted testing for familial variants (also called site-specific or known variants testing) is available for the MYH9 gene. See FMTT / Familial Variant, Targeted Testing, Varies. To obtain more information about this testing option, call 800-533-1710.
Shipping Instructions
Specimen preferred to arrive within 96 hours of collection.
Necessary Information
Platelet Esoteric Testing Patient Information is required. Testing may proceed without the patient information, however, the information aids in providing a more thorough interpretation. Ordering providers are strongly encouraged to fill out the form and send with the specimen.
Specimen Required
Specimen Type: Whole blood
Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.
Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Yellow top (ACD)
Specimen Volume: 3 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send whole blood specimen in original tube. Do not aliquot.
Specimen Stability Information: Ambient (preferred) 4 days/Refrigerated
Forms
1. Platelet Esoteric Testing Patient Information is required.
2. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing (Spanish) (T826)
3. If not ordering electronically, complete, print, and send an Coagulation Test Request (T753) with the specimen.
Useful For
Evaluating MYH9-related disorders, including May-Hegglin disorder/anomaly and Sebastian syndrome, in patients with a personal or family history suggestive of an MYH9-related disorder
Diagnosing MYH9-related disorders, including May-Hegglin disorder/anomaly and Sebastian syndrome, for patients in whom phenotypic testing is nondiagnostic, but there is a strong clinical suspicion of the MYH9-related disorder
Confirming an MYH9-related disorder diagnosis with the identification of a known or suspected disease-causing alteration in the MYH9 gene
Determining the disease-causing alterations within the MYH9 gene to delineate the underlying molecular defect in a patient with a laboratory diagnosis of an MYH9-related disorder
Identifying the causative alteration for genetic counseling purposes
Prognosis and risk assessment based on the genotype-phenotype correlations
Providing a prognosis in syndromic MYH9-related disorders
Carrier testing for close family members of an individual with an MYH9-related disorder diagnosis
This test is not intended for prenatal diagnosis
Special Instructions
Method Name
Sequence Capture and Targeted Next-Generation Sequencing (NGS) followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing.
Reporting Name
MYH9 Gene, Full Gene NGSSpecimen Type
VariesSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Varies | ||
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Clinical Information
Platelets have essential roles in primary hemostasis. Patients with either hereditary or acquired platelet disorders usually have bleeding diathesis, which can potentially be life-threatening, and may also have issues with the development and/or functioning of major organs.(2) Inherited platelet disorders can be syndromic (ie, associated with current or future development of other organ system defects) or nonsyndromic (ie, isolated to thrombocytopenia with no other organ system defects).
A reliable laboratory diagnosis of a platelet disorder can significantly impact patients' and, potentially, their family members' clinical management and outcome. Identification of an alteration that is known or suspected to cause disease aids in confirmation of the diagnosis and, potentially, provides prognostic information especially in the syndromic inherited platelet disorders.
This test evaluates the MYH9 gene, which is associated with a variety of MYH9-related disorders, including May-Hegglin disorder/anomaly, Sebastian syndrome, Fechtner syndrome, Epstein syndrome, MYH9-related syndromic thrombocytopenia, macrothrombocytopenia and granulocyte inclusions with or without nephritis or sensorineural hearing loss, and macrothrombocytopenia with leukocyte inclusions.
The risk for developing bleeding or other phenotypic features associated with these disorders and syndromes varies. The MYH9 gene has established bleeding, thrombocytopenia, and syndromic risk, and also expert group guidelines.(1,3-5)
It is recommended that genetic testing be offered to all patients suspected of having a heritable platelet disorder since some patients may have normal platelet laboratory testing results.(1,6) Genetic testing is integral to the conclusive diagnosis of an MYH9-related disorder.(5,6)
Reference Values
An interpretive report will be provided.
Day(s) Performed
Varies
Report Available
28 to 42 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
81479