A fast hemoglobin variant on newborn screening is associated with alpha-thalassemia trait.
Alpha thalassemia trait (alpha-thal-1) is a common cause of microcytosis in black and Asian populations. A small amount of hemoglobin Barts (2-8%) is transiently present in affected infants at birth and detectable in many newborn screening laboratories; it is a fast-moving hemoglobin on electrophoresis. In order to determine whether a report of a "fast hemoglobin variant" on newborn hemoglobinopathy screening is associated with a diagnosis of alpha thalassemia trait, hemoglobin concentration, red blood cell indices, and peripheral blood smear examination were performed on 18 infants referred for hematologic evaluation of a "fast hemoglobin variant" on newborn screening. All 18 infants with this diagnosis referred for consultation were black; ages ranged from 24 to 86 days (median 40 days). Six of 18 infants (33%) were mildly anemic for age and all 18 were microcytic. The prevalence of a "fast variant" among infants born at our institution is 2.5%. In that conditions other than alpha-thal-1 that cause microcytosis in early infancy are very uncommon, we conclude that all 18 of our infants with a fast hemoglobin on newborn screening likely have alpha-thal-1. The newborn screening result is thus a commonly and readily available laboratory report that specifically supports a diagnosis of alpha-thal-1, a diagnosis with significant clinical and genetic implications that is usually made only by exclusion.
Miller
S T
ST
Children's Medical Center of Brooklyn, State University of New York-Health Science Center at Brooklyn, USA.
Desai
N
N
Pass
K A
KA
Rao
S P
SP
D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D017085:alpha-Thalassemia / Q000097:blood / Q000175:diagnosis*
D006454:Hemoglobins