spherocytosis

Spherocytosis is an inherited disorder of the red blood cells. It is the most common (1 in 2,000 of Northern European ancestry) disorder of the red cell membrane, the bag which contains the hemoglobin molecules that carry oxygen through the blood stream.

Most cases of spherocytosis are hereditary with autosomal dominant inheritance. A few cases are apparently autosomal recessive, and interestingly enough, about 25% are thought to be new mutations.

The disease is characterised by abnormal red blood cell membrane proteins which cause the cell to assume a spherical shape rather than the usual "doughnut with a filled in center" shape. The abnormal cells that result from this pass with greater difficulty through the spleen (an abdominal blood filtering organ tucked up under the left ribcage where old blood cells are normally removed from circulation) and are consequently destroyed abnormally fast.

In newborns, the chief manifestation of this disease is a hemolytic anemia which can be quite severe. The excessive rate of breakdown of red cells in the baby's bloodstream can cause severe jaundice and may require exchange transfusion. Definitive treatment of spherocytosis is surgical removal of the spleen, but this is delayed as long as possible in children (usually age 5 or 6) because of the vital role the spleen plays in protecting us against overwhelming infections. Some children have such mild disease that they do not require splenectomy; they seem to be the minority. Children with spherocytosis require immunization against the pneumococcus bacterium and prohylactic antibiotic treatment as well to lessen the risk of sepsis.

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