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Disease Profile

MYH9 related thrombocytopenia

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

1-9 / 1 000 000

US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

MYH9 related disorders; Sebastian syndrome (subtype); May-Hegglin anomaly (subtype);


Blood Diseases


MYH9-related thrombocytopenia (MYH9RD) is a genetic condition caused by mutations in the MYH9 gene and is characterized by large platelets and thrombocytopenia (low number of platelets) which increases the risk for mild to serious bleeding in the body or in the skin. Young-adult onset high frequency sensorineural hearing loss, presenile (early) cataract, and kidney disease also variably occurs in people with this condition.[1] This condition is inherited in an autosomal dominant fashion.

The following conditions, once thought to be separate, are now known to be part of MYH9RD. 

Epstein syndrome 
Fechtner syndrome 
May-Hegglin anomaly 
Sebastian syndrome


This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Congenital thrombocytopenia
30%-79% of people have these symptoms
Bruising susceptibility
Bruise easily
Easy bruisability
Easy bruising

[ more ]

Elevated hepatic transaminase
High liver enzymes
Giant platelets
Abnormally heavy bleeding during menstruation
Kidney inflammation
Neutrophil inclusion bodies
Presenile cataracts
Prolonged bleeding time
High urine protein levels
Protein in urine

[ more ]

Renal insufficiency
Renal failure
Renal failure in adulthood

[ more ]

Sensorineural hearing impairment
Spontaneous, recurrent epistaxis
Recurring nosebleed
Spontaneous, recurrent nosebleed

[ more ]

1%-4% of people have these symptoms
Myocardial infarction
Heart attack
Percent of people who have these symptoms is not available through HPO
Abnormal thrombosis
Abnormal blood clot
Autosomal dominant inheritance
Bloody nose
Frequent nosebleeds
Nose bleed
Nose bleeding

[ more ]

Leukocyte inclusion bodies
Low platelet count


Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.
  • Orphanet lists international laboratories offering diagnostic testing for this condition.


    There is currently no cure for MYH9-related thrombocytopenia. Measures that can be taken to prevent bleeding episodes may include platelet transfusion, desmopressin, or antifibrinolytic drug administration prior to surgery or invasive procedures, and regular dental care to prevent bleeding of the gums. People with MYH9RD should avoid drugs that inhibit platelet function or blood coagulation, activities with high risk for injury, ototoxic drugs, hazardous noise, nephrotoxic agents (agents that are toxic to the kidneys), glucocorticoids (steroids) and radiation therapy. Bleeding episodes are treated with platelet transfusion and sometimes with desmopressin (this helps to shorten bleeding time in some people). People with bleeding episodes should be monitored for anemia. Once a year urine analysis (including 2-hour protein) and a measurement of serum concentration of creatinine should be done to monitor for kidney disease. Hearing and vision evaluations are needed every three years prior to onset of hearing loss and cataracts. Kidney complications, hearing loss, and cataracts are all managed in a standard fashion.[1]


    Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

    Organizations Supporting this Disease

      Organizations Providing General Support

        Learn more

        These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

        Where to Start

        • MedlinePlus Genetics contains information on MYH9 related thrombocytopenia. This website is maintained by the National Library of Medicine.

          In-Depth Information

          • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
          • Medscape Reference has information on May-Hegglin anomaly which includes information on other MYH9-related thrombocytopenias. You may need to register to view this medical reference, but registration is free.
          • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
          • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
          • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
          • PubMed is a searchable database of medical literature and lists journal articles that discuss MYH9 related thrombocytopenia. Click on the link to view a sample search on this topic.


            1. Savoia A, Balduini CL. MYH9-Related Disorders. GeneReviews. 2011; https://www.ncbi.nlm.nih.gov/books/NBK2689/. Accessed 4/11/2012.

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