Abstract
Thirty-four blood samples of neonates in Dubai, UAE, with an MCV below 90 fL were checked by high performance liquid chromatography (HPLC) for hemoglobin variants to confirm a previous study carried out in Western Province of Saudi Arabia which showed a very high predictive index of such MCV for alpha (α-) thalassemia minor (ATM). MCH below 30 pg was an additional factor which supported such a prediction. The Dubai study confirmed the original finding with 100% of such neonates showing Hb Barts band. A control group of 26 neonates with an MCV between 90 and 95 fl showed Hb Barts in only 11 cases (42.3%). Of these, 6 (23.1%) were preterm babies, expected to have higher MCV. Five cases (19.2%) had an MCH below 30 pg, though MCV was 90 or higher. Three of the preterm babies also had MCH below 30. The study confirmed the Saudi results in neonates. It seems very highly probable that a term neonate with MCV below 90 and MCH below 30 has ATM.
Highlights
The presence of Hb Barts in blood at birth is a finding in α-thalassemia trait, intermedia (HbH disease) and major.[1,2] Diagnosis of α-thalassemia major is not a problem and it is incompatible with life[3] as most of the hemoglobin will be Barts
The problem lies with α-thalassemia trait, single or double gene deletion types. Most of these cases have normal HbA2 levels if checked after the age of six months,[6,7,8] though red cell indices are thalassemic. This group, which makes up the bulk of gene carriers, will be difficult to confirm by Hb electrophoresis (HBEP) or by high performance liquid chromatography (HPLC) in childhood and adult life
After the work carried out in Jeddah, Saudi Arabia,[6] where the population is basically local with a low expatriate mix, as well as some variation in the origin of the local population itself, it was thought useful to the medical literature to repeat the study at another site to confirm the remarkable results of the original study
Summary
The presence of Hb Barts in blood at birth is a finding in α-thalassemia trait, intermedia (HbH disease) and major (hydrops fetalis).[1,2] Diagnosis of α-thalassemia major is not a problem and it is incompatible with life[3] as most of the hemoglobin will be Barts. Neonates with α-thalassemia intermedia have HbF, HbA and Hb Barts, usually more than 15%.4 This condition is easy to diagnose later in life, even if not investigated at birth, due to the presence of HbH.[6]. The problem lies with α-thalassemia trait, single or double gene deletion types Most of these cases have normal HbA2 levels if checked after the age of six months,[6,7,8] though red cell indices are thalassemic. This group, which makes up the bulk of gene carriers, will be difficult to confirm by Hb electrophoresis (HBEP) or by HPLC in childhood and adult life. There was a need to repeat the study in another setting, where thalassemics are of variable ethnic groups, like in Dubai. α-thalassemia is present in the UAE nationals and residents of Iranian, Arab, Pakistani and Filipino origins in Dubai and it was expected that neonates in such a population would make a good sample for repetition of the study and confirmation of the validity of using the MCV and MCH as predictive parameters in individuals of various ethnic groups
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