Abstract
Hereditary erythroblastic anaemia was found in a homozygous mutant (hea/hea) of an inbred strain CFO, which originated from noninbred CF#1 mice from Carworth Inc. This newly-described anaemia is inherited as an autosomal recessive and is lethal at 15-25 days of age. Erythrocytes of anaemic mice show striking polychromasia, anisocytosis, and poikilocytosis. One of the most marked features of this anaemia is the presence of large numbers of nucleated cells, mainly orthochromatophilic erythroblasts and myeloid cells, in the circulation. They also include immature erythroid and myeloid cells. Many naked nuclei appear on smears from circulating blood of anaemic infants. Erythrocytes, haematocrit percentage, and haemoglobin content of older anaemic infants were only about 50% of those of the normal. Formation of erythroid, myeloid cells, and megakaryocytes in the bone marrow seems to be progressively affected by mutant alleles in the anaemic infants.