National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Overhydrated hereditary stomatocytosis



Other Names:
Potassium sodium disorder of erythrocyte; Stomatocytosis I
Categories:

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.
orphanet

Orpha Number: 3203

Definition
Overhydrated hereditary stomatocytosis (OHSt) is a disorder of red cell membrane permeability to monovalent cations and is characterized clinically by hemolytic anemia.

Epidemiology
OHSt is very rare with only seven cases described in the literature so far.

Clinical description
Onset occurs during the neonatal period or infancy with hemolytic anemia that may require occasional blood transfusions. Splenomegaly or hepatosplenomegaly are present. The disease course is marked by the usual complications of hemolytic anemia (biliary lithiasis) and, remarkably, by a strong tendency for iron overload.

Etiology
In the majority of cases, OHSt is caused by mutations in the RHAG gene (6p21-qter) encoding the Rh-associated glycoprotein component of the Rh complex.

Diagnostic methods
Diagnosis is based on a massive right shift of the osmotic gradient ektacytometry curve indicating overhydrated red cells and decreased osmotic resistance, together with a substantial increase in the monovalent cation leak compared to controls, and a sharp decrease of the leak as a function of decreasing temperature. Blood smears show an elevated percentage of well formed stomatocytes. There is macrocytosis, a low mean cell hemoglobin concentration (MCHC) and a high reticulocyte count. Electrophoresis reveals that the membrane protein stomatin is absent or present at only low levels.

Differential diagnosis
The differential diagnosis should include the most common form of hereditary stomatocytosis, dehydrated hereditary stomatocytosis, as well as hereditary cryohydrocytosis with reduced stomatin (see these terms).

Genetic counseling
OHSt is transmitted as an autosomal dominant trait but de novo mutations are quite common.

Management and treatment
Treatment involves blood transfusions, when necessary, together with management of biliary lithiasis and iron overload. Splenectomy is contraindicated in OHSt patients as it may induce venous thromboembolic complications.

Prognosis
With correct management of the complications, the prognosis is good.

Visit the Orphanet disease page for more resources.
Last updated: 10/1/2008

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.

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Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Abnormal mean corpuscular volume 0025065
Decreased mean corpuscular hemoglobin concentration 0025547
Hemolytic anemia 0001878
Increased red cell osmotic fragility 0005502
Reticulocytosis
Increased immature red blood cells
Increased number of immature red blood cells
[ more ]
0001923
Stomatocytosis 0004446
5%-29% of people have these symptoms
Abnormal thrombosis
Abnormal blood clot
0001977
Anisocytosis
Unequal size of red blood cells
0011273
Increased lactate dehydrogenase level 0025435
Intermittent jaundice
Intermittent yellow skin
Intermittent yellowing of skin
[ more ]
0001046
Splenomegaly
Increased spleen size
0001744
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance 0000006
Hepatomegaly
Enlarged liver
0002240
Hyperbilirubinemia
High blood bilirubin levels
0002904
Increased intracellular sodium 0003575
Jaundice
Yellow skin
Yellowing of the skin
[ more ]
0000952
Showing of 16 |
Last updated: 7/1/2020

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.

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources


Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • The Centers for Mendelian Genomics program is working to discover the causes of rare genetic disorders. For more information about applying to the research study, please visit their website.

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.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, 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 Overhydrated hereditary stomatocytosis. Click on the link to view a sample search on this topic.

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