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WILLIAM'S HEMATOLOGY > 47 Erythrocyte Membrane Disorders > Flashcards

47 Erythrocyte Membrane Disorders Flashcards

1
Q

The lipid bilayer comprises approximately _____% of the membrane mass

A

50%

Contains unesterified cholesterol and phospholipids in approximately equal amounts, with small amounts of glycolipids and phosphoinositides

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2
Q

TRUE OR FALSE

Mature erythrocytes are unable to synthesize fatty acids, phospholipids, or cholesterol de novo, and they depend on lipid exchange and limited phospholipid repair.

A

TRUE

Mature erythrocytes are unable to synthesize fatty acids, phospholipids, or cholesterol de novo, and they depend on lipid exchange and limited phospholipid repair.

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3
Q

lt regulates the fluidity of the membrane and is present in both leaflets

A

Cholesterol

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4
Q

Located in the outer leaflet and play a role in plasma lipid exchange and renewal of membrane phospholipids

A

Phosphatidylcholine and sphingomyelin

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5
Q

Location in the lipid bilayer

Red cell antigens (A, B, H, and P): ________
Aminophospholipids: phosphatidylserine and phosphatidylethanolamine: ___________

A

Red cell antigens (A, B, H, and P): EXTERNAL
Aminophospholipids: phosphatidylserine and phosphatidylethanolamine: INTERNAL

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6
Q

The asymmetric distribution of phospholipids is maintained by a dynamic process involving ________that translocate the aminophospholipids to the inner and outer leaflets, respectively

A

Flippase (ATP11C) and Floppase enzymes

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7
Q

Asymmetry of the phospholipids is important for the survival of the erythrocyte because exposure of ___________on the cell surface, as found in sickle cell disease and thalassemia, has several deleterious consequences

A

Phosphatidylserine

○ It activates the coagulation cascade and may contribute to thromboses;
○ it facilitates adhesion to the vascular endothelium;
○ it provides a recognition signal for macrophages to phagocytose these cells; and
○ it decreases the interaction of skeletal proteins with the bilayer, which destabilizes the membrane.

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8
Q

Lipid rafts are anchored to ________ and play a role in signaling and invasion of malaria parasites

A

Spectrin

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9
Q

2 classifications of membane proteins:

A

Integral
Peripheral

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10
Q

Embedded in the lipid bilayer, functions as transport proteins, receptors, signaling molecules, and carriers of red cell antigens

Require detergents to extract them

A

Integral or transmembrane proteins

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11
Q

Constitute the membrane skeleton and are loosely attached to the cytoplasmic face of the lipid bilayer and can be extracted by high or low salt concentrations or by high pH

Function either as structural proteins and form part of the membrane skeleton or they serve as linker proteins attaching the skeleton to the bilayer

A

Peripheral proteins

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12
Q

The most abundant and important erythrocyte transmembrane proteins

A

Anion exchanger-1 (AE1)
Glycophorins (GPs)

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13
Q

Gene ecoding anion exchanger-1 (AE1)

A

SLC4A1 gene previously known as band 3

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14
Q

Responsible for most of the external negative charge of red cells glycophorins, which prevents the adherence of cells to each other and the vascular endothelium

A

Sialic acid

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15
Q

Function as receptors for Plasmodium falciparum, the most virulent malaria parasite

A

Glycophorins

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16
Q

Other Integral Membrane Proteins

A

Rh-RhAG group of proteins
Ion pumps and channels
Cation and anion transporters

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17
Q

Plays a critical role in maintaining the shape and integrity of the red cell

A

Peripheral Membrane Proteins

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18
Q

Major proteins of the erythrocyte membrane skeleton

A

Spectrin, actin, proteins 4.1R, 4.2, 4.9, p55, and the adducins

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19
Q

Mediate the vertical attachment of the skeleton to integral membrane proteins in the lipid bilayer

A

Linker proteins

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20
Q

The primary connecting protein which links spectrin to the cytoplasmic domain of AE1, as well as to the Rh/RhAG complex

A

Ankyrin

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21
Q

Major constituent of the erythrocyte membrane skeleton

A

Spectrin

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22
Q

Provides the red cell with elasticity and durability to withstand the shear stress encountered in the circulation

A

Spectrin

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23
Q

Maintain the biconcave disk shape of the red cell, regulate the lateral mobility of integral membrane proteins, and provide structural support for the lipid bilayer

A

Spectrin

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24
Q

Behaves like a reversible spring, which may contribute to the elasticity of the membrane

A

Ankyrin

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25
Q

Form of protein 4.1R that is predominating in young erythrocytes

A

Protein 4.1b

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26
Q

A member of the transglutaminase family of proteins, but it has no enzyme activity because it lacks the critical triad of residues that form the active transglutaminase site

A

Protein 4.2

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27
Q

A calcium/calmodulin-binding phosphoprotein located at the spectrin–actin junctional complex

A

Adducin

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28
Q

A trimeric phosphoprotein that acts as a linker molecule by binding to the transmembrane GLUT-1

A

Dematin or protein 4.9

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29
Q

Composition of the ankyrin complex

A

AE1, GPA, Rh, and RhAG complex proteins
Ankyrin, protein 4.2, and several glycolytic enzymes

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30
Q

Composition of the distal junctional complex

A

AE1, GPC, GLUT-1, Rh, Kell, and XK proteins

Proteins 4.1R, actin, dematin, adducin, tropomyosin, tropomodulin, and p55.5

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31
Q

The membrane skeleton resembles a lattice-like network, with approximately ______% of the lipid bilayer directly laminated to the underlying skeleton

A

60%

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32
Q

The (horizontal or vertical) protein interactions are important in the maintenance of the structural integrity of the cell, accounting for the high tensile strength of the erythrocyte

A

Horizontal

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33
Q

The (horizontal or vertical) protein–protein interactions are critical in the stabilization of the lipid bilayer, preventing loss of microvesicles from the cells

A

Vertical

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34
Q

Average life span of RBCs

A

120 days

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35
Q

3 features that regulate the deformability of RBCs:

A

(a) the biconcave disk shape (a high ratio of surface area to cellular volume)
(b) the viscoelastic properties of the membrane (spectrin)
(c) the cytoplasmic viscosity

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36
Q

Characteristic of RBC that provides a high ratio of surface area to cellular volume and this excess of membrane is critical for survival of the cell

A

Biconcave disk shape

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37
Q

Cytoplasmic viscosity is determined primarily by the ____________

A

Intracellular hemoglobin concentration

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38
Q

The major determinant of membrane stability

A

The horizontal interactions of the peripheral proteins of the junctional complex, mainly protein 4.1R and actin, which link the tail ends of the spectrin tetramers together

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39
Q

As the mean cell hemoglobin concentration rises above _________, the viscosity increases exponentially

A

370 g/L

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40
Q

The hemoglobin concentration is critically dependent on red cell volume, which is primarily determined by the ___________

A

Total cation content of the cell

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41
Q

The red cell membrane maintains a _______ potassium, ________ sodium, and________calcium content within the cell.

A

High potassium
Low sodium
Very-low calcium

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42
Q

Extrudes 3 sodium ions in exchange for 2 potassium ions entering the red cell

A

Na+K+ ATPase

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43
Q

Calcium is pumped out of the cell by this channel

Protects the cell from deleterious effects of calcium, such as echinocytosis, membrane vesiculation, calpain activation, membrane proteolysis, and cellular dehydration

A

Calmodulin-activated Ca2+ ATPase

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44
Q

The Ca2+-activated K+ channel, also called the _____________

It causes selective loss of K+ in response to increased intracellular Ca2+

A

Gardos channel

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45
Q

Chloride and bicarbonate anions are readily exchanged through ____

A

AE1

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46
Q

Water is transported by

A

Aquaporin-1 (AQP1)

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47
Q

Vertical or Horizontal proteins

Result in destabilization of the bilayer, loss of membrane microvesicles and spherocyte formation

A

Vertical

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48
Q

Vertical or Horizontal proteins

Disrupt the skeleton resulting in defective shape recovery and elliptocytes

A

Horizontal

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49
Q

The most common cause of HE
and HPP

A

Functional self-association defect in α-Spectrin

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50
Q

Protein defect that cause “Acanthocytic” spherocytes present on blood film presplenectomy

A

β-Spectrin

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51
Q

Deficiency of ___________ is the most common cause of HS in North America

A

Ankyrin

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52
Q

Deficiency is the most common cause of HS in parts of Europe and South Africa

“Pincered” spherocytes are common on blood film presplenectomy

A

AE1

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53
Q

Deficiency primarily found in Japanese patients with HS

A

Protein 4.2

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54
Q

Protein defect in Ankyrin and Protein 4.2 cause

A

HS recessive

The stabilizing effect of the transmembrane section of AE1 on the lipid bilayer is lost, facilitating the formation of AE1-free microvesicles

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55
Q

SAO is caused by defect in what protein

A

AE1

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56
Q

Defect in this protein cause “acanthocytic” spherocytes

A

Beta spectrin

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57
Q

Defect in this protein cause “pincered” spherocytes

A

AE1

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58
Q

The hallmark of HS erythrocytes

A

Loss of membrane surface area relative to intracellular volume

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59
Q

TRUE OR FALSE

The spleen plays a secondary, but important, role in the pathophysiology of HS.

A

TRUE

The spleen plays a secondary, but important, role in the pathophysiology of HS.

Spherocytes are retained and ultimately destroyed in the spleen and this is the primary cause of the chronic hemolysis experienced by HS patients

The degree of splenic retention correlated with the reduction in the surface-area-to-volume ratio.

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60
Q

In approximately 75% of HS patients, inheritance is _________________

A

Autosomal dominant

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61
Q

Mutations of these genes are associated with recessive HS

A

α-spectrin or protein 4.2

62
Q

Approximately _________ of HS patients have moderate disease

A

60% to 70%

63
Q

Approximately________ of HS patients have moderately severe disease, as evidenced by indicators of anemia that are more pronounced than in typical moderate HS, and an intermittent requirement for transfusions

A

5% to 10%

64
Q

A small number (________%) of patients have severe disease with life-threatening anemia and are transfusion dependent.

A

<5%

They almost always have recessive HS.
Most have severe spectrin deficiency

65
Q

In children with HS ,_______ is the most frequent finding (50% of cases)

A

Anemia

**Followed by splenomegaly, jaundice, or a positive family history

66
Q

TRUE OR FALSE

No proven correlation exists between the spleen size and the severity of HS

A

TRUE

No proven correlation exists between the spleen size and the severity of HS

67
Q

Characteristics of patients with severe HS

A

Recessive HS
Severe spectrin deficiency
Irregularly contoured or budding spherocytes or bizarre poikilocytes

68
Q

Most common finding in neonates with HS

A

Jaundice

69
Q

Most frequently reported complication in as many as half of HS patients

A

Bilirubinate gallstones

70
Q

The most common crisis in HS, which is usually associated with viral illnesses. Generally mild and characterized by jaundice, splenomegaly, anemia, and reticulocytosis

A

Hemolytic crisis

71
Q

The most common etiologic agent in aplastic crisis

A

Parvovirus

Aplastic crises usually last for 10–14 days and may bring asymptomatic, undiagnosed HS patients with compensated hemolysis to medical attention

72
Q

May occur in HS patients with increased folate demands, such as pregnant patients, growing children, or patients recovering from an aplastic crisis

A

Megaloblastic crises

73
Q

TRUE OR FALSE

Leg ulcers, chronic dermatitis on the legs and gout are rare manifestations of HS, which usually do not heal even after splenectomy.

A

FALSE

Leg ulcers, chronic dermatitis on the legs and gout are rare manifestations of HS, which usually heal rapidly after splenectomy.

74
Q

Most patients have mild to moderate anemia with hemoglobin in the _________range

A

90–120 g/L

75
Q

TRUE OR FALSE

Mean corpuscular volume is increased because of relative cellular dehydration in approximately half of patients, but all HS patients have some hydrated cells

A

FALSE

Mean corpuscular hemoglobin concentration (MCHC) is increased (>36 g/dL) because of relative cellular dehydration in approximately half of patients, but all HS patients have some dehydrated cells

76
Q

TRUE OR FALSE

Mean corpuscular volume (MCV) is usually normal except in cases of severe HS, when MCV is slightly decreased.

A

TRUE

Mean corpuscular volume (MCV) is usually normal except in cases of severe HS, when MCV is slightly decreased.

77
Q

TRUE OR FALSE

Spherocytes typically swell and burst at lower sodium chloride concentrations than do normal biconcave disk-shaped red cells.

A

FALSE

Spherocytes typically swell and burst at HIGHER sodium chloride concentrations than do normal biconcave disk-shaped red cells.

78
Q

A fluorescent dye that binds to the transmembrane proteins, AE1, Rh protein, Rh glycoprotein, and CD47

A

Eosin 5′-maleimide (EMA)

79
Q

Expected finding of HS in Eosin 5′-Maleimide Flow Cytometry Test

A

Decreased fluorescence compared to controls

80
Q

This useful test monitors red cell deformability under a continuous osmotic gradient and a known shear stress, which generates a deformability index profile.

A

Osmotic Gradient Ektacytometry

81
Q

Expected finding of HS in Osmotic Gradient Ektacytometry

A

Decreased maximum deformability index combined with an increased minimum osmotic (Omin) gradient

82
Q

This test identifies the underlying defective protein after separation of the red cell membrane proteins by SDS-PAGE

A

Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis

83
Q

TRUE OR FALSE

All the laboratories used at least 2 tests to make a final diagnosis of HS, as none of the currently available methods have 100% sensitivity.

A

TRUE

All the laboratories used at least 2 tests to make a final diagnosis of HS, as none of the currently available methods have 100% sensitivity.

84
Q

In neonatal HS, HS ratio (MCHC divided by MCV) of greater than_______has a very high sensitivity and specificity

A

0.36

85
Q

The primary determinant of erythrocyte survival in HS patients

A

Splenic sequestration

86
Q

TRUE OR FALSE

Postsplenectomy, spherocytosis, and altered osmotic fragility persist, but the “tail” of the osmotic fragility curve, created by conditioning of a subpopulation of spherocytes by the spleen, disappears.

A

TRUE

Postsplenectomy, spherocytosis, and altered osmotic fragility persist, but the “tail” of the osmotic fragility curve, created by conditioning of a subpopulation of spherocytes by the spleen, disappears.

87
Q

HS patients candidate for splenectomy

A
  • transfusion-dependent severe spherocytosis
  • significant signs or symptoms of anemia
  • growth failure, skeletal changes, leg ulcers, and extramedullary hematopoietic tumors
  • patients suffering from vascular compromise of vital organs
88
Q

Because the risk of postsplenectomy sepsis is very high during infancy and early childhood, splenectomy should be delayed until age ______ years if possible and to at least ______years if feasible

A

5 to 9 years

3 years

89
Q

Postsplenectomy prophylactic antibiotics

A

Penicillin V 125 mg orally twice daily for patients younger than 7 years or
250 mg orally twice daily for those older than 7 years, including adults

90
Q

Presplenectomy and, in severe cases, post-splenectomy, HS patients should take folic acid (______mg/day orally) to prevent folate deficiency.

A

Folic acid (1 mg/day orally)

91
Q

Reasons for splenectomy failure:

A

Missed accessory spleen
Development of splenunculi as a consequence of autotransplantation of splenic tissue during surgery
Another intrinsic red cell defect, such as pyruvate kinase deficiency

92
Q

Accessory spleens occur in ____% to ____% of patients and must always be sought.

A

15% to 40%

93
Q

Definitive confirmation of ectopic splenic tissue

A

Radiocolloid liver– spleen scan or
Scan using 51Cr-labeled, heat-damaged red cells

94
Q

The erythrocytes from these patients exhibited increased thermal sensitivity. Seen in patients suffering from severe burns

A

HEREDITARY PYROPOIKILOCYTOSIS

95
Q

The primary abnormality in HE erythrocytes

A

Defective HORIZONTAL interactions between components of the membrane skeleton

96
Q

The most common defects in HE and HPP

A

Spectrin

Mutations that affect spectrin heterodimer self-association are found in the majority of HE patients and in all patients with HPP.

97
Q

The primary abnormality in HPP erythrocytes

A

Combination of HORIZONTAL (impaired spectrin tetramer formation) and VERTICAL (spectrin deficiency) defects

98
Q

Carry the Gerbich antigens and rare patients with the Leach phenotype are Gerbich negative and lack both GPs

A

Glycophorin C and D

99
Q

The most important determinants of the severity of hemolysis in HE

A

Percentage of spectrin dimers and the spectrin content of the membrane skeleton

100
Q

The most common polymorphism affecting spectrin content and clinical severity

A

αLELY, the low-expression Lyon α-spectrin allele

101
Q

HE is typically inherited as an _________ disorder.

A

Autosomal dominant

102
Q

TRUE OR FALSE

HPP is an autosomal recessive disorder and a strong genetic relationship exists between HE and HPP, whereby parents or siblings of patients with HPP often have typical HE.

A

TRUE

HPP is an autosomal recessive disorder and a strong genetic relationship exists between HE and HPP, whereby parents or siblings of patients with HPP often have typical HE.

103
Q

TRUE OR FALSE (Clinical presentation)

The overwhelming majority of patients with HPP are asymptomatic and are diagnosed incidentally

HE patients present in infancy or early childhood with severe hemolytic anemia

A

FALSE

The overwhelming majority of patients with HE are asymptomatic and are diagnosed incidentally

HPP patients present in infancy or early childhood with severe hemolytic anemia

104
Q

Hereditary Elliptocytosis and Pyropoikilocytosis in Infancy

Typically, elliptocytes do not appear on the blood film until the patient is _________

A

4–6 months old

These patients may require red cell transfusion, phototherapy, or exchange transfusion.

Usually, even in severely affected patients, the hemolysis abates between 9 and 12 months of age, and the patient progresses to typical HE with mild anemia.

105
Q

The hallmark of HE

A

Presence of cigar-shaped elliptocytes on blood films

106
Q

TRUE OR FALSE

The degree of hemolysis does not correlate with the number of elliptocytes present.

A

TRUE

The degree of hemolysis does not correlate with the number of elliptocytes present.

107
Q

Blood smear features of HPP

A

Extreme poikilocytosis, some bizarre-shaped cells with fragmentation or budding, and often only very few or no elliptocytes

108
Q

Prominent cells on blood films of neonates with HPP

A

Pyknocytes

109
Q

Causes of acquired elliptocytosis

A

Megaloblastic anemias, hypochromic microcytic anemias (iron-deficiency anemia and thalassemia), myelodysplastic syndromes, and myelofibrosis

110
Q

Acquired elliptocytosis generally represents less than _______ of red cells seen on the blood film.

A

25%

111
Q

An artifact of blood film preparation and these cells are found only in certain areas of the film, usually near its tail. The long axes of are parallel

A

Pseudoelliptocytosis

112
Q

Other name for SOUTH-EAST ASIAN OVALOCYTOSIS

A

Melanesian elliptocytosis or stomatocytic elliptocytosis

113
Q

SAO is characterized by the presence of large oval red cells, many of which contain ____________

A

1 or 2 transverse ridges or a longitudinal slit

At least 20% ovalocytic red cells

Notable absence of clinical and laboratory evidence of hemolysis

114
Q

Sturctural abnormality in SAO

A

AE1(SLC4A1 gene )

115
Q

Spiculated red cells are classified into 2 types:

A

A.Acanthocytes
B. Echinocytes

116
Q

What cell is being described:

Contracted, dense cells with irregular projections from the red cell surface that vary in width and length

A

Acanthocytes

117
Q

What cell is being described:

Small, uniform projections spread evenly over the circumference of the red cell

A

Echinocytes

118
Q

Normal adults may have as many as____% of spiculated erythrocytes

A

3%

119
Q

Conditions where spiculated cells are seen

A

After transfusion with stored blood
Ingestion of alcohol and certain drugs
Exposure to ionizing radiation or certain venoms
Hemodialysis
Functional or actual splenectomy
Severe liver disease
Severe uremia
Abetalipoproteinemia
Inherited neurologic disorders
Abnormalities of the Kell blood group
Glycolytic enzyme defects
Myelodysplasia
Hypothyroidism
Anorexia nervosa
Vitamin E deficiency
Premature infants
Suppressed expression of Lua and Lub

120
Q

The anemia in patients with liver disease is often called

A

Spur-cell anemia

121
Q

Pathogenesis of spur cell anemia

A

Accumulation of free (nonesterified) cholesterol in the red cell membrane

Remodeling of abnormally shaped red cells by the spleen

122
Q

Clinical features of spur cell anemia

A

Rapidly progressive hemolytic anemia with large numbers of acanthocytes on the blood film

123
Q

Spur-cell anemia is most common in patients with _______________,

A

Alcoholic liver disease

124
Q

TRUE OR FALSE

Splenectomy for spur cell anemia is a dangerous and potentially fatal procedure in these critically ill patients and is recommended

A

FALSE

Splenectomy is a dangerous and potentially fatal procedure in these critically ill patients and is not recommended

125
Q

The prognosis for patients with alcoholic liver disease and more than ____% spur cells is very poor.

A

5%

126
Q

Only effective treatment option for spur cell anemia

A

A liver transplant combined with alcohol abstinence

127
Q

Common features are a degeneration of neurons and abnormal acanthocytic erythrocyte morphology

A

NEUROACANTHOCYTOSIS

128
Q

Types of neuroacanthocytosis syndromes:

A

(a) lipoprotein abnormalities (abetalipoproteinemia and hypobetalipoproteinemia)

(b) neural degeneration of the basal ganglia (chorea-acanthocytosis and McLeod syndrome)

(c) movement abnormalities (Huntington disease-like 2 (HDL2) and pantothenate kinase-associated neurodegeneration)

129
Q

Very rare autosomal recessive disorder characterized by progressive ataxic neurologic disease, malabsorption of dietary fat and lipid-soluble vitamins (A, D, E, and K), retinal degradation, and acanthocytosis

Absent or extremely low low-density lipoprotein cholesterol, triglyceride, and apoB levels.

A

Abetalipoproteinemia / Bassen-Kornzweig syndrome

130
Q

The primary molecular defect in abetalipoproteinemia

A

Lack of the microsomal triglyceride transfer protein (MTTP)

An essential cofactor for the assembly and secretion of lipoprotein particles that contain apolipoprotein B (apoB)

131
Q

The altered plasma lipid profile affects in Abetalipoproteinemia: phosphatidylcholine content is __________ with a corresponding ___________ in sphingomyelin.

A

Phosphatidylcholine: decreased
Sphingomyelin: increased

132
Q

Primary cause of the neuropathy in Abetalipoproteinemia

A

Marked vitamin E deficiency

133
Q

Rare autosomal-recessive movement disorder characterized by atrophy of the basal ganglia and progressive neurodegenerative disease with onset in adolescence or early adult life.

The lipoproteins are normal.

A

Chorea-Acanthocytosis Syndrome

134
Q

Causative gene in Chorea-Acanthocytosis Syndrome

A

VPS13A (vacuolar protein sorting 13 homologue A) codes for chorein

135
Q

Rare X-linked disorder of the Kell blood group system, whereby cells react poorly with Kell antisera, with cardiomyopathy

A

McLeod Syndrome

136
Q

Causative gene in McLeod Syndrome

A

XK protein

137
Q

Rare disorder caused by expanded CGT/CAG trinucleotide repeats in exon 2A of the Junctophilin-3 (JPH3) gene on chromosome 16q24.3

Features encompass involuntary movements, neuropsychiatric symptoms, and cognitive defect; autosomal dominant and Africa ancestry

A

HDL2

138
Q

Characterized by progressive dystonia, and cognitive impairment in childhood, but no anemia

Mutations in the PANK2 gene on chromosome 20p.13 coding for pantothenate kinase 2

A

Pantothenate kinase-associated neurodegeneration (Hallervorden-Spatz syndrome)

139
Q

Cup-shaped red cells characterized by a central hemoglobin-free area

A

Stomatocytes

140
Q

Cells which are formed when there is net loss of cations dehydrates the cells

A

Xerocytes

141
Q

Causative genes in:

Over-hydration syndromes:
Dehydration syndromes:

A

Over-hydration syndromes: RHAG, SLC4A1, and GLUT1

Dehydration syndromes: PIEZO1 and KCNN4

142
Q

The most common form of the cation permeability defects.

Characterized by an efflux of K+

May also exhibit pseudohyperkalemia and perinatal edema

A

Hereditary xerocytosis, also known as dehydrated hereditary stomatocytosis

143
Q

Defective gene in Hereditary xerocytosis

A

PIEZO1

KCNN4 (minority): Gardos channel, a calcium-activated K+ channel

144
Q

TRUE OR FALSE

Splenectomy does not significantly improve the anemia in Hereditary Xerocytosis

A

TRUE

Splenectomy does not significantly improve the anemia, which suggests that xerocytes are detected and eliminated in other areas of the reticuloendothelial system.

145
Q

Very rare heterogeneous disorder characterized by a marked passive sodium leak, which increases the water content of the cell and causes macrocytosis

A

OVERHYDRATED HEREDITARY STOMATOCYTOSIS

146
Q

Pathogenesis of Hereditary hydrocytosis

A

Lack of stomatin

Less often, very low levels of this 31-kDa integral membrane protein

147
Q

Gene mutations associated with Hereditary hydrocytosis

A

NO gene mutations have been found, which implies that the absence of the protein is a secondary phenomenon.

RhAG
SLC4A1

148
Q

Exhibits as mild cation leak that is markedly enhanced at low temperatures

Associated with mild to moderate hemolytic anemia, and splenectomy appears to have little or no effec

A

Cryohydrocytosis

149
Q

Gene mutations associated with Hereditary hydrocytosis

A

GLUT1 gene

150
Q

Are very rare cases where the clinical phenotype and biochemical features of some patients with stomatocytes are intermediate between the extremes of hereditary hydrocytosis and hereditary xerocytosis.

A

Intermediate syndromes

151
Q

A rare condition that leads to accumulation of cholesteryl esters in many tissues, resulting in clinical findings of large orange tonsils and hepatosplenomegaly.

A

Familial deficiency of high-density lipoproteins

152
Q

Causes of scquired stomatocytosis

A

Acute alcoholism
Vinca alkaloids
Long-distance runners immediately after a race

WILLIAM'S HEMATOLOGY (89 decks)

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