Unexpected Discovery of Hemoglobin D Iran Families in Punjab, Pakistan by using two different Screening Methods

Abstract

Background: Hemoglobin D Iran is frequently misdiagnosed as Hb E or Hb D Punjab if only one method of screening is used. The objective of our study was to highlight the importance of using two different screening techniques in diagnosis of a hemoglobin variant, Hb D Iran in our case. Hematological parameters of heterozygous Hb D Iran and compound heterozygous β/Hb D Iran were also compared. Methods: A descriptive study was carried out on results of 52,379 subjects which were part of thalassemia extended family cascade screening from 36 districts of Punjab from October 2019-March 2021. Cases of Hb D Punjab and Hb E were run on both CE-HPLC (cation exchange-high performance liquid chromatography) and CZE (capillary zone electrophoresis). Resulting Hb D Iran cases were confirmed by ARMS-PCR (Amplification refractory mutation system-polymerase chain reaction). Results: Forty cases of Hb D Iran were detected out of 160 initially suspected Hb D Punjab cases and 126 Hb E cases. Diagnosis was confirmed by molecular analysis. Statistical significance was found between RBC count, MCV, MCH, Hb F and diagnosis of “heterozygous Hb D Iran” and “compound heterozygous for β/ Hb D Iran”. Conclusion: Hb D Iran can be easily missed and misdiagnosed as Hb E or Hb D Punjab, if two screening methods are not used. This maybe a reason why Hb D Iran remains unreported in our region. CBC and HPLC indices can also be suggestive if a case is of heterozygous D Iran or compound heterozygous β/Hb D Iran. Keywords: Hb D Iran, Hb E, Hb D Punjab, Cation exchange High performance liquid chromatography, Capillary zone electrophoresis