Hereditary Elliptocytosis

Elliptocytes are erythrocytes that are oval to elliptical in shape. They are a normal finding in birds, reptiles, amphibians, fish, and members of the Camelidae family (camels, llamas, alpacas). In other mammals, elliptocytosis (ovalocytosis) is an uncommon change of erythrocytes (red blood cells) due to inherited or acquired disease. Hereditary elliptocytosis (HE)has been documented in humans, dogs, and mice as a result of erythrocyte membrane protein mutation or deficiency.

There is no treatment needed for the disorder unless red blood cells rupture. Surgery to remove the spleen may decrease red blood cell rupture. Most Individuals with hereditary elliptocytosis have no problems. Elliptocytosis is frequently harmless. In mild cases, fewer than 15% of red blood cells are oval-shaped. However, some animals may have crises in which the red blood cells rupture, releasing their hemoglobin. Persons with this disease can develop anemia, jaundice, and gallstones.

In both humans and dogs, HE is inherited as an autosomal recessive trait. In dogs, HE is primarily a result of protein deficiency. However, previous mutations in protein coupled with a deficiency of protein also causes HE. HE has been documented in mixed breed dogs and in a Silky Terrier.

Diseases Associated with Elliptocytosis

Elliptocytosis in dogs may be associated with inherited or acquired diseases: Membrane protein deficiency (hereditary), myelofibrosis (acquired), protein mutation and deficiency (hereditary), myelodysplastic syndrome (acquired).

In cats the following acquired conditions may causes elliptocytosis:

• Myeloproliferative disease
• Acute Lymphoblastic Leukemia
• Hepatic Lipidosis
• Portosystemic shunt
• Doxorubicin toxicity

Diagnosis of Elliptocytosis

• CBC (complete blood count) may show anemia or cell destruction.
• A smear of the blood may show elliptical red blood cells.
• Bilirubin may be high.
• LDH may be high.
• Cholecystogram (x-ray of gallbladder) may show gallstones.

Signs of Elliptocytosis

The clinical signs of hereditary elliptocytosis in the dog are minimal to none, and the disease usually is diagnosed incidentally. Theoretically, dogs with HE could have severe hemolytic anemia, but this has not been documented yet.

References

1. Angela M. Ehinger, DVM; Kenneth S. Latimer, DVM, PhD; Bruce E. LeRoy, DVM, Dipl. ACVP; Perry J. Bain, DVM, PhD. Elliptocytosis and Ovalocytosis in Stained Blood Smears. Veterinary Clinical Pathology Clerkship Program