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MedGen UID:
Concept ID:
Laboratory or Test Result
Synonyms: erythrocyte stomatocytes; Red cell stomatocytosis
HPO: HP:0004446


The presence of erythrocytes with a mouth-shaped (stoma) area of central pallor on peripheral blood smear. [from HPO]

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVStomatocytosis

Conditions with this feature

Hereditary cryohydrocytosis with reduced stomatin
MedGen UID:
Concept ID:
Disease or Syndrome
Stomatin-deficient cryohydrocytosis with neurologic defects is an autosomal dominant disorder characterized by delayed psychomotor development, seizures, cataracts, and pseudohyperkalemia resulting from defects in the red blood cell membrane. The disorder combines the neurologic features of Glut1 deficiency syndrome-1 (GLUT1DS1; 606777), resulting from impaired glucose transport at the blood-brain barrier, and hemolytic anemia/pseudohyperkalemia with stomatocytosis, resulting from a cation leak in erythrocytes (summary by Bawazir et al., 2012). For a discussion of clinical and genetic heterogeneity of red cell stomatocyte disorders, see 194380.
Rh-null, regulator type
MedGen UID:
Concept ID:
Disease or Syndrome
The RH-null phenotype designates rare individuals whose red blood cells lack all Rh antigens. Two RH-null types, the regulator type (RHNR) and the amorph type (RHNA; 617970), arising from independent genetic mechanisms have been distinguished. The regulator type is caused by mutation in the RHAG gene (180297), which encodes the Rh50 glycoprotein that is crucial for the surface disposition of Rh antigens. The amorph type arises from mutations at the RH locus itself that silence Rh expression. The RH locus contains the RHD (111680) and RHCE (111700) genes tandemly arranged at chromosome 1p36-p34. Four genes must therefore be silenced to produce the RH-null phenotype. The absence of the D antigen, produced by the RHD gene, is common in the human population; the D-negative phenotype may result from deletion or genetic alteration of the RHD gene. The absence of D antigen defines the Rh-negative status of the human erythrocyte (summary by Huang et al., 2000). Whereas Rh-null cells lack all Rh antigens, Rh-mod cells display a markedly reduced antigen expression. Clinically, Rh-deficient individuals exhibit a mild to moderate chronic hemolytic anemia accompanied by a varying degree of spherostomatocytosis (summary by Huang et al., 1999).
MedGen UID:
Concept ID:
Disease or Syndrome
Cryohydrocytosis (CHC) is an exceedingly rare condition characterized by a mild stomatocytic hemolytic state with hyperbilirubinemia. A hallmark of this condition is that red blood cells (RBCs) lyse on storage at 4 degrees centigrade. RBC cation permeability is increased at 37 degrees centigrade, and the cells also accumulate sodium in the cold (summary by Coles et al., 1999). Patients present with fatigue, mild anemia, and pseudohyperkalemia due to a potassium leak from the RBCs (summary by Bogdanova et al., 2010). For a discussion of clinical and genetic heterogeneity of the hereditary stomatocytoses, see 194380.
Overhydrated hereditary stomatocytosis
MedGen UID:
Concept ID:
Disease or Syndrome
Overhydrated hereditary stomatocytosis is a variably compensated macrocytic hemolytic anemia of fluctuating severity, characterized by circulating erythrocytes with slit-like lucencies (stomata) evident on peripheral blood smears. OHST red cells exhibit cation leak, resulting in elevated cell Na+ content with reduced K+ content, with increased ouabain-resistant cation leak fluxes in the presence of presumably compensatory increases in ouabain-sensitive Na(+)-K(+) ATPase activity, and red cell age-dependent loss of stomatin/EBP7.2 (EBP72; 133090) from the erythroid membrane. Clinically, patients with OHST exhibit overhydrated erythrocytes and a temperature-dependent red cell cation leak. The temperature dependence of the leak is 'monotonic' and has a steep slope, reflecting the very large leak at 37 degrees centigrade (summary by Bruce, 2009 and Stewart et al., 2011). For a discussion of clinical and genetic heterogeneity of the hereditary stomatocytoses, see 194380.
Hemolytic anemia due to erythrocyte adenosine deaminase overproduction
MedGen UID:
Concept ID:
Disease or Syndrome
Hemolytic anemia due to elevated adenosine deaminase (HAEADA) is an X-linked hematologic disorder characterized by onset of mild to moderate red cell anemia soon after birth or in childhood. The anemia is associated with significantly increased activity of ADA (608958) specifically in erythrocyte precursors. ATP levels may be secondarily decreased. Additional features may include low birth weight, thrombocytopenia, hypospadias, and splenomegaly. Males are preferentially affected, although carrier females may show elevated erythrocyte ADA or mild features (Ludwig et al., 2022).
Sitosterolemia 1
MedGen UID:
Concept ID:
Disease or Syndrome
Sitosterolemia is characterized by: Hypercholesterolemia (especially in children) which (1) shows an unexpected significant lowering of plasma cholesterol level in response to low-fat diet modification or to bile acid sequestrant therapy; or (2) does not respond to statin therapy; Tendon xanthomas or tuberous (i.e., planar) xanthomas that can occur in childhood and in unusual locations (heels, knees, elbows, and buttocks); Premature atherosclerosis, which can lead to angina, aortic valve involvement, myocardial infarction, and sudden death; Hemolytic anemia, abnormally shaped erythrocytes (stomatocytes), and large platelets (macrothrombocytopenia). On occasion, the abnormal hematologic findings may be the initial presentation or the only clinical feature of this disorder. Arthritis, arthralgias, and splenomegaly may sometimes be seen and one study has concluded that "idiopathic" liver disease could be undiagnosed sitosterolemia. The clinical spectrum of sitosterolemia is probably not fully appreciated due to underdiagnosis and the fact that the phenotype in infants is likely to be highly dependent on diet.
Bernard-Soulier syndrome, type A2, autosomal dominant
MedGen UID:
Concept ID:
Disease or Syndrome
Autosomal dominant Bernard-Soulier syndrome type A2 (BSSA2) is characterized by chronic macrothrombocytopenia with mild or no clinical symptoms, normal platelet function, and normal megakaryocyte count. When present, clinical findings include excessive ecchymoses, frequent epistaxis, gingival bleeding, prolonged menstrual periods, or prolonged bleeding after tooth extraction (Savoia et al., 2001). Genetic Heterogeneity of Bernard-Soulier Syndrome Homozygous or compound heterozygous mutations in the GP1BA gene cause classic autosomal recessive Bernard-Soulier syndrome (BSSA1; 231200).

Professional guidelines


Russo R, Andolfo I, Manna F, Gambale A, Marra R, Rosato BE, Caforio P, Pinto V, Pignataro P, Radhakrishnan K, Unal S, Tomaiuolo G, Forni GL, Iolascon A
Am J Hematol 2018 May;93(5):672-682. Epub 2018 Feb 24 doi: 10.1002/ajh.25058. PMID: 29396846
Bolton-Maggs PH, Stevens RF, Dodd NJ, Lamont G, Tittensor P, King MJ; General Haematology Task Force of the British Committee for Standards in Haematology
Br J Haematol 2004 Aug;126(4):455-74. doi: 10.1111/j.1365-2141.2004.05052.x. PMID: 15287938
Bolton-Maggs PH
Baillieres Best Pract Res Clin Haematol 2000 Sep;13(3):327-42. doi: 10.1053/beha.2000.0081. PMID: 11030038

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