Alpha thalassemia and the hematology of homozygous sickle cell disease in childhood

Alpha thalassemia modifies the gematolic expression of homozygous sickle cell (SS) disease, resulting in increased total hemoglobin and HbA2 and decreased HbF, mean cell volume, reticulocytes, irreversibly sickled cells, and biliru-bin levels. The age at which these changes develop in children with SS disease is unknown. Ascertainment of globin gene status in a large representative sample of study the gematologic indices in nine children homozygous for Alpha thalassemia 2 (two-gene group), 90 children heterozygous for Alpha thalassemia 2 (three-gene group), and 167 children with a normal Alpha globin gene complement (four-gene group). The two-gene group had significantly lower mean cell volumes from birth, higher red cell counts from one month, lower reticulocytes from three months, and higher HbA2 levels from one year, as compared with the four-gene group. Children with three genes had intermediate indices but resembled more closely the four-gene group. Differences in total hemoglobin or in fetal hemoglobin between the groups were not apparent by eight years of age. The most characteristic differences of the two-gene group were the raised proportional HbA2 level and low mean cell volume, the latter having some predictive value for Alpha thalassemia status at birth.(AU)

Haematological change in sickle cell-haemoglobin C disease and in sickle cell-beta thalassaemia: a cohort study from birth

The haematological changes in early years following neonatal diagnosis have been observed in representative groups of children with sickle cell-haemoglobin C (SC) disease, sickle cell-á+ thalassaemia, and in sickle cell-á Thalassaemia. Most haematological indices in SC disease were intermediate between previously published values in SS disease and in AA controls, generally being closer to values in normal children, Eceptions were microcytosis which may be genetically determined and a striking elevation of mean cell haemoglobin cocentration from age 2 months to 4 years. The combination of a raised MCHC and a lowered MCV is unusual and may be characteristic of SC disease. Features in sickle cell-á thalassaemaia generally differed accordingly to the type of á thalassaemia gene. Sickle cell-B degree thalassaemia had lower levels of haemoglobin, MCHC, red cell count, MCV, and higher reticulocytes, most differences being significant before 1 year. No differences between SB degree thalassaemia and Sá+ thalassaemia were apparent in HbF levels (which resembled those in SS disease) or in HbA2 levels (which exceeded those in SS disease by 1 year of age).(AU)