MedGen

Red cell pyruvate kinase deficiency is the most common cause of hereditary nonspherocytic hemolytic anemia. PK deficiency is also the most frequent enzyme abnormality of the glycolytic pathway (Zanella et al., 2005). [from OMIM]

Any hereditary spherocytosis in which the cause of the disease is a mutation in the ANK1 gene. [from MONDO]

People with the mild form may have very mild anemia or sometimes have no symptoms. People with the moderate form typically have anemia, jaundice, and splenomegaly. Many also develop gallstones. The signs and symptoms of moderate hereditary spherocytosis usually appear in childhood. Individuals with the moderate/severe form have all the features of the moderate form but also have severe anemia. Those with the severe form have life-threatening anemia that requires frequent blood transfusions to replenish their red blood cell supply. They also have severe splenomegaly, jaundice, and a high risk for developing gallstones. Some individuals with the severe form have short stature, delayed sexual development, and skeletal abnormalities.

There are four forms of hereditary spherocytosis, which are distinguished by the severity of signs and symptoms. They are known as the mild form, the moderate form, the moderate/severe form, and the severe form. It is estimated that 20 to 30 percent of people with hereditary spherocytosis have the mild form, 60 to 70 percent have the moderate form, 10 percent have the moderate/severe form, and 3 to 5 percent have the severe form.

Hereditary spherocytosis is a condition that affects red blood cells. People with this condition typically experience a shortage of red blood cells (anemia), yellowing of the eyes and skin (jaundice), and an enlarged spleen (splenomegaly). Most newborns with hereditary spherocytosis have severe anemia, although it improves after the first year of life. Splenomegaly can occur anytime from early childhood to adulthood. About half of affected individuals develop hard deposits in the gallbladder called gallstones, which typically occur from late childhood to mid-adulthood. [from MedlinePlus Genetics]

EPB42-related hereditary spherocytosis (EPB42-HS) is a chronic nonimmune hemolytic anemia that is usually of mild-to-moderate severity. EPB42-HS can present with jaundice as early as the first 24 hours of life or can present later in childhood with anemia resulting from a hemolytic crisis or aplastic crisis (usually associated with a viral infection). In addition to the hematologic manifestations, serious complications include splenomegaly, which can become evident in early childhood, and cholelithiasis, which usually becomes evident in the second or third decade of life. Typical laboratory findings in EPB42-HS include anemia (decreased hemoglobin [Hgb] level) and reticulocytosis (increased percentage of reticulocytes), with high mean corpuscular Hgb concentration, presence of spherocytes in the peripheral blood smear, significantly decreased or absent haptoglobin, mildly increased osmotic fragility in osmotic fragility assay, increased Omin (osmolality at which 50% of red blood cells hemolyze), and decreased maximal elongation index (EImax) in osmotic gradient ektacytometry. [from GeneReviews]

People with the mild form may have very mild anemia or sometimes have no symptoms. People with the moderate form typically have anemia, jaundice, and splenomegaly. Many also develop gallstones. The signs and symptoms of moderate hereditary spherocytosis usually appear in childhood. Individuals with the moderate/severe form have all the features of the moderate form but also have severe anemia. Those with the severe form have life-threatening anemia that requires frequent blood transfusions to replenish their red blood cell supply. They also have severe splenomegaly, jaundice, and a high risk for developing gallstones. Some individuals with the severe form have short stature, delayed sexual development, and skeletal abnormalities.

There are four forms of hereditary spherocytosis, which are distinguished by the severity of signs and symptoms. They are known as the mild form, the moderate form, the moderate/severe form, and the severe form. It is estimated that 20 to 30 percent of people with hereditary spherocytosis have the mild form, 60 to 70 percent have the moderate form, 10 percent have the moderate/severe form, and 3 to 5 percent have the severe form.

Hereditary spherocytosis is a condition that affects red blood cells. People with this condition typically experience a shortage of red blood cells (anemia), yellowing of the eyes and skin (jaundice), and an enlarged spleen (splenomegaly). Most newborns with hereditary spherocytosis have severe anemia, although it improves after the first year of life. Splenomegaly can occur anytime from early childhood to adulthood. About half of affected individuals develop hard deposits in the gallbladder called gallstones, which typically occur from late childhood to mid-adulthood. [from MedlinePlus Genetics]

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. [from OMIM]

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). [from OMIM]

The RH-null phenotype designates rare individuals whose red blood cells lack all Rh antigens. Two RH-null types, the regulator type (RHNR; 268150) and the amorph type (RHNA), arising from independent genetic mechanisms have been distinguished. The regulator type is caused by mutation in the RHAG gene (180297). The amorph type arises from mutations at the RH locus itself that silence Rh expression. The RH locus contains the RHD (111680) and RHCE 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 RH-null amorph phenotype thus arises from inactivating mutations in RHCE on a D-negative background (summary by Huang et al., 1998 and Huang et al., 2000). Clinically, Rh-null patients present mild to moderate hemolytic anemia; cells exhibit characteristic morphologic and functional abnormalities including spherocytosis, stomatocytosis, and diminished lifespan. Rh-null patients rarely develop antibodies without stimulation, and most cases occur in response to pregnancy or transfusion (Silvy et al., 2015). [from OMIM]