Dilemmas in Considering β-Thalassemia Status in Subjects with Borderline HbA2 Values: A Pilot Study in Eastern India

Tridip Chatterjee,Amit Chakravarty,Sudipa Chakravarty

doi:10.4081/thal.2014.2103

Abstract

Interpreting hemoglobin disorders by high performance liquid chromatography can sometimes deceptive, especially with borderline HbA2 values. It is often problematic, especially in antenatal cases if the partner is a known thalassemia trait. We tested for underlying β-thalassemia mutations in 24 subjects with borderline HbA2 values (between 3.0%-4.0%). Amplification refractory mutation system-polymerase chain reaction was used to detect the five common Indian β-thalassemia mutations: [IVS-I-5 (G>C), Cod 15 (G-A), Cod 8/9 (+G), Fr. 41/42 (-TTCT) and Cod 26 (G-A)]. β-globin gene sequencing was performed if no mutation was detected. β-globin gene defect was not identified in any of the samples. There was no presence of any of the five common mutations in the small cohort. The average value of HbA2 in 24 normal samples was found to be 3.96. The average values for mean cell volume and mean cell hemoglobin (MCH) were found to be 82 and 28.8 pg respectively. Among these 24 normal samples, 13 had MCH below 27 pg and 11 had MCH above 27 pg. On the contrary, one thalassemic family was screened, in which the father of an HbE-β thalassemia patient was found to have HbA2 3.1, being a β-thalassemia carrier. Mutation analysis should be offered to all at-risk couples with borderline HbA2, especially those with values between 3.5% and 4.0% and microcytic hypochromic indices. As, cases with some specific mutational background or clinical condition shows abnormally low HbA2, so mutation screening should be performed in other partner if one partner found to be carrier or patient of thalassemia.

Highlights

Introduction cal committeePeripheral blood samples were mutations of Eastern India[2,3,4] like IVS1-1 (Gcollected from every participant in the various T), IVS1-5 (G-C), codon 8/9 (+G), codon 26 (G-screening camps, in vials containing 5 mM A), and Fr. 41/42 (−TCTT)
Those, who were confirmed of their status by these studies, were taken for evaluation for determining the b-thalassemia mutations
The participants were evaluated for Hb, one thalassemic family was screened, in which ing the b-thalassemia diseased or carrier sta- MCV, MCH, mean cell hemoglobin concentrathe father of an HbE-b thalassemia patient was tus especially in this mixed population of West tion, red cell distribution width (RdW), hematfound to have HbA2 3.1, being a b-thalassemia Bengal, Eastern part of India with lots of ethnic ocrit

Summary

Introduction

Introduction cal committeePeripheral blood samples were mutations of Eastern India[2,3,4] like IVS1-1 (Gcollected from every participant in the various T), IVS1-5 (G-C), codon 8/9 (+G), codon 26 (G-screening camps, in vials containing 5 mM A), and Fr. 41/42 (−TCTT). Those, who were confirmed of their status by these studies, were taken for evaluation for determining the b-thalassemia mutations.

Results

Conclusion