Hereditary xerocytosis is characterized by red cell
membrane abnormality with increased permeability to cations and a greater
efflux of potassium than of sodium. Consequently, these red cells lose
potassium in excess of sodium gained, with a decrease in total cation
content. Osmotically resistant xerocytes result. Clinically, the patient may
present with episodes of fatigue, jaundice, pallor, and darkened urine,
especially during intense physical activity. At the other end of the
spectrum from xerocytosis is hereditary stomatocytosis (or hydrocytosis), in
which the red cells are overhydrated and sodium loaded.
Hereditary Hyperphosphatidylcholine Hemolytic Anemia;
Dehydrated Hereditary Stomatocytosis; Hereditary Desiccytosis.
Approximately 1:10,000 kindreds in France and the United
Autosomal dominant. Mutation located on
chromosome 16, but the gene is not yet identified. Hereditary xerocytosis
differs from other stomatocytoses in that the stomatin protein (or
“erythrocyte membrane protein 7.2b”) is not missing from the red cell
The red blood cells have a membrane abnormality
with increased permeability to cations, with a greater efflux of potassium
than of sodium. Consequently, these red cells lose potassium in excess of
sodium gained, with a decrease in total cation content. Osmotically
resistant xerocytes result.
Laboratory findings include hemoglobinuria, increased
red cell hemolysis by shear stress, increased mean corpuscular volume, and
increased mean corpuscular hemoglobin concentration.
Patients generally have few symptoms but may have
exercise-induced episodes of fatigue, associated with jaundice, pallor, or
darkened urine. Splenomegaly and cholelithiasis may occur. Hemoglobin levels
are often normal or near-normal, despite clinical and laboratory evidence of
mild-to-moderate hemolysis. Transfusions are generally not required, and the
benefit of splenectomy is slight. Iron overload may develop later in life.
Check hemoglobin level and
Potential reduction in oxygen delivery
as a consequence of decreased levels of 2,3-diphosphoglycerate.
No known specific implications with
Hereditary Spherocytosis: Genetically transmitted hemolytic
anemia caused by mutations in the spectrin gene in people of
circum-Mediterranean descent. Autosomal dominant and recessive forms are
Hereditary Stomatocytosis: Series of inherited red blood cell
disorders in which the outer membrane of the cell “leaks” sodium and
Autosomal dominant hemolytic medical condition in which erythrocytes have a
bizarre morphology similar to that seen in thermal burns. Probably caused by
coinheritance of a mutation impairing spectrin association (and causing
hereditary elliptocytosis) and a second mutation that results in
quantitative spectrin deficiency.
Carella M, Stewart G, Ajetunmobi J, et al: Genomewide search for
dehydrated hereditary stomatocytosis (hereditary xerocytosis): Mapping of
locus to chromosome 16 (q23-qter). Am J Hum Genet 63:8106, 1998.
Entazami M, Becker R, Mensen H, et al: Xerocytosis with concomitant
intrauterine ascites: First description and therapeutic approach. Blood 90:5392,