Abstract
Newborns with alpha thalassemia trait have microcytic red blood cells (RBCs) used as a diagnostic screening tool at birth. Infants with beta thalassemia present with microcytosis sometime during the first year of life; however, whether microcytosis is present in newborns is unknown. In this study, we determined the MCV and MCH values in newborn infants, who have beta0 thalassemia major, intermedia, and minor by performing a retrospective study, with IRB approval.
189 eligible patients seen by the hematology/oncology group of 10 physicians at Children's Hospital Medical Center (CHMC) and UNMC were reviewed. Patients were identified by International Classification Codes-10 (56.1, 56.3, 57.3, 57.4). Of the 189 eligible patients with beta thalassemia major, intermedia, minor, and sickle cell trait (used as controls), there were 28 evaluable and 161 non-evaluable patients. The non-evaluable patients had either the wrong diagnosis (coexisting alpha thalassemia trait) (68) or no laboratory data within the newborn period or up to 6 months of age (93). A second control group used were normal complete blood count (CBC) values by age from the Pathology Laboratory at CHMC. Of the 28 evaluable infants, 5 had beta0 thalassemia major, 2 had sickle-beta+ thalassemia (regarded as intermedia for this study), 7 had beta thalassemia minor, and 14 had sickle cell trait. The diagnosis in each of the 28 infants was confirmed by newborn screening for a hemoglobinopathy and hemoglobin electrophoresis sometime after birth. The MCV, MCH, mean corpuscular hemoglobin concentration (MCHC), hemoglobin (hgb), hematocrit (hct), and red blood cell count (RBC) were taken on evaluable patients within the newborn period through 6 months of age and de-identified using the Safe Harbor Method.
MCV and MCH were found to be reduced in newborns with beta0 thalassemia and sickle-beta+ thalassemia. However, infants with beta thalassemia minor had normal MCV and MCH values. The MCHC, RBC, hgb, and hct were comparable to controls and within normal limits. By 3-4 months of age, in the infants with beta thalassemia major or intermedia, the MCV and MCH fell to clinically characteristic levels when compared to controls, and plateaued through 6 months of age. MCV and MCH values for infants with beta thalassemia minor, 0-6 months of age, were incomplete to be able to draw a similar conclusion.
The proposed mechanism for microcytosis in major and intermedia is an imbalance between alpha and beta globin chain synthesis, which is not apparent in newborns with minor.
In conclusion, the MCV and MCH can be used to screen for beta0 thalassemia major and intermedia in newborns. Although the data are discriminating despite the small numbers, a prospective study should confirm these findings.
No relevant conflicts of interest to declare.
