Dehydrated hereditary stomatocytosis

Dehydrated hereditary stomatocytosis (DHS), also known as hereditary xerocytosis or desiccytosis, is a rare inherited red blood cell membrane disorder characterized by increased red blood cell permeability to cations, leading to a net loss of intracellular potassium and water. This results in dehydrated, dense erythrocytes that are prone to premature destruction (hemolysis). The condition primarily affects the hematologic system, though secondary complications can involve the liver and spleen. DHS is the most common form of the hereditary stomatocytosis syndromes and is most frequently caused by mutations in the PIEZO1 gene, which encodes a mechanically activated ion channel, or less commonly in the KCNN4 gene. Key clinical features include mild to moderate hemolytic anemia, jaundice (particularly during the neonatal period), reticulocytosis, elevated mean corpuscular hemoglobin concentration (MCHC), and splenomegaly. Some patients may present with perinatal edema or hydrops fetalis. The severity of symptoms is highly variable, even within the same family, and some individuals may be nearly asymptomatic. A characteristic finding on blood smear is the presence of stomatocytes and target cells, though stomatocytes may be few in number. Patients are at increased risk of iron overload, which can occur even without transfusion therapy, and pseudohyperkalemia (falsely elevated potassium levels in vitro) is a recognized laboratory artifact. Treatment is primarily supportive. Folic acid supplementation is commonly recommended to support red blood cell production. Splenectomy is generally contraindicated in DHS because it does not significantly improve anemia and is associated with a markedly increased risk of thromboembolic complications, including portal vein thrombosis and pulmonary embolism. Monitoring and management of iron overload with chelation therapy may be necessary. Blood transfusions are occasionally required during hemolytic crises or severe anemia. Neonatal cases with hydrops fetalis may require intrauterine or postnatal transfusions.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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