Hemoglobin E

The HbE mutation (p26 Glu!Lys; GAG! AAG) occurs almost exclusively in Southeast Asia, Bangladesh, northeast India, and Sri Lanka. It is the most common abnormal hemoglobin in this region and reaches a carrier frequency of at least 50% at the border of Thailand, Cambodia, and Laos. HbE has become more frequently encountered in Europe and North America with increased Southeast Asian and Bengali immigration. The protective effect of

HbE against severe malaria may be related to an unidentified membrane abnormality that renders most of the RBC population relatively resistant to invasion by Plasmodium falciparum.[14]

Individuals with HbE trait or homozygous HbE have hypochromic microcytosis and a modest anemia, but HbE/ p-thalassemia can cause severe, transfusion-dependent anemia.[15] In fact, globally, HbE/p-thalassemia is the most prevalent form of p-thalassemia major. In Southeast Asia, HbE may also be coinherited with one of several endemic a-globin abnormalities (including HbCS) and cause complex thalassemia syndromes.[13]

In high-risk populations, the England-Fraser discriminant function [MCV - RBC - (5 x Hb) - 3.4] may be helpful in identifying individuals carrying HbE.[16] HbE is distinguished by characteristic electrophoretic mobilities on alkaline and acid gels, properties on anion/cation-exchange HPLC, and mild insolubility. Of note, coinher-itance of HbE with a-thalassemia may confound routine diagnostic investigations because the hemoglobin interactions can lead to reduced HbE levels and altered hematologic features.

Newborn screening programs need to incorporate strategies to distinguish the relatively benign homozygous HbE state from HbE/p-thalassemia. Hemoglobin quanti-tation by HPLC is helpful in this regard; newborn infants with HbE/p-thalassemia have lower HbE percentages and different HbF/HbE ratios compared to HbE homozygotes. DNA analysis using multiplex allele-specific PCR will confirm the presence of HbE and distinguish the homozygous HbE from HbE/p-thalassemia genotypes.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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