Homozygotes provide a molecular and phenotypic model of hereditary spherocytosis type 3 and a phenotypic model for hereditary spherocytosis type 1 and some aspects of sickle cell anemia. Most phenotypic assessment has been performed using F1 homozygous offspring of heterozygotes from the C57BL/6J and WB/Re congenic strains or homozygotes generated on a B6;WB segregating background. Approximately half die by 6 months of age. Homozygotes display hemolytic anemia with spherocytosis, microcytosis, reduced hematocrit, reticulocytisis, extramedullary hematopoiesis in the spleen and liver, lymphocytosis, neutrophilia, lymph node hyperlasia, and cardiac hypertrophy. Homozygotes can be identified within the first day of birth by their jaundiced color. Consequent to the underlying disorder, homozygotes are prone to developing gallstones, pneumonitis, and vaso-occulsive disease in multiple organs.
