Erythrocyte Membrane Defects (Schalms’ 30)

Question 1

What transmembrane protein deficiency in cattle leads to hereditary spherocytosis?

Answer 1

Band 3

Question 2

How does Band 3 deficiency in cattle lead to increased erythrocyte fragility?

Answer 2

1) Disruption of the spectrin, ankyrin, actin, and protein 4.2 skeletal network and decreased mechanical stability
2) Defective anion exchange of Cl/HCO3 and alteration of acid/base homeostasis

Question 3

Spectrin and ankyrin deficiencies have been reported in what species?

Answer 3

Mice, leading to life-threatening hemolytic anemia and fragile, short-lived spherocytes

Question 4

Hereditary elliptocytosis in dogs is caused by a deficiency of what protein?

Answer 4

Protein 4.1

Question 5

What two proteins are bound by protein 4.1?

Answer 5

Spectrin and actin

Question 6

Hereditary stomatocytosis occurs in what breeds?

Answer 6

1) Miniature and standard schnauzers
2) Chondrodysplastic Alaskan Malamute Dwarf dogs

Question 7

What is the best screening test for nonimmune hereditary red cell membrane disorders?

Answer 7

Osmotic gradient ektacytometry
(An instrument that monitors the extend of RBC shape change within a particular osmotic gradient under a known shear stress)

Question 8

Defective amino acid transmembrane transport results in what deficiency in erythrocytes? What are the signs? What breeds has this been reported in?

Answer 8

1) Glutathione deficiency
2) Heinz bodies and increased oxidant sensitivity, shortened RBC lifespan - Finnish Landrace Sheep
3) 30% of thoroughbred horses with no clinical signs