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hereditary stomatocytosis (cryohydrocytosis)
Pathology:
- erythrocyte anomaly associated with hemolytic anemia
- increased Na+/K+-permeability, thus disorder of cell volume control
- associated with stomatin deficiency
Genetics:
- autosomal dominant
- hereditary stomatocytosis associated with
- mutations in the band 3 chloride-bicarbonate exchanger AE1/SLC4A1
- mutations in the erythroid ammonia channel Rh-associated glycoprotein (RHAG)
- mutations in erythroid glucose transporter SLC2A1/GLUT1
Clinical manifestations:
- many patients present with neonatal hemolytic anemia
- others are asymptomatic throughout life
Laboratory:
- complete blood count
- anemia
- MCV as high as 110-150 fL hydrocytes
- Coulter counter overestimates size of xerocytes
- WBC count & platelet count generally normal
- reticulocyte count is elevated with hemolysis
- peripheral blood smear
- 5-50% stomatocytes; < 3% is normal
- osmotic fragility test
- overhydrated stomatocytosis are osmotically fragile
- dehydrated stomatocytosis are resistant to osmotic lysis
Complications:
- aplastic crises associated with parvovirus infection
- iron overload is common
- adults may be diagnosed with hemochromatosis
- complications of hemolysis
- cholilithiasis
Management:
- folic acid for significant hemolysis
- chelation with deferoxamine for iron overload
General
stomatocytosis; hydrocytosis; xerocytosis
genetic disease of the blood/bone marrow
References
- UniProt :accession P27105
- Kanwar VS and Coppes MJ
eMedicine: Hereditary Disorders of Red Cell Permeability
http://emedicine.medscape.com/article/955921-overview