Abnormal Erythrocyte Morphology Abnormal Hemoglobin Concentration SCDO (Jade Hotchkiss) SCDO:1000186 Sufficient Any deviation from the normal concentration of hemoglobin in the blood. HP:0020061 It might seem wrong to place this class here, but note that a change in hemoglobin concentration affects the size/volume and hence morphology of erythrocytes. Perhaps add sub-classes "Increased hemoglobin concentration" and "Decreased hemoglobin concentration" from HPO...their descriptions don't seem quite right though (should it not rather be "in the erythrocytes", not "in the circulation"? Protein Phenotype