PMC6002971_01
CE-HPLC showing characteristic peak of HbDIran/beta0 thal [cds 41/42 (-CTTT)].
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PMC6002971_01_gr1.jpg
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Hb A2 window [82.8%; retention time (RT): 3.57 min] with low Hb A0 and Hb F peaks (4.6% and 1.0%, respectively) (Figure 1). The possibility of homozygous Hb E was ruled out by the absence of a band in the position of Hb A2/Hb E by Hb electrophoresis. Hence, the case was initially suspected to be a rare finding of Hb Tianshui, which has similar alkaline Hb electrophoresis and
(A) DNA sequence chromatogram showing HbDIran mutation on 22 codon (GAA>CAG). (B) DNA sequence chromatogram showing beta0 thal {4 bp del Cds 41/42 (-CTTT)}
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PMC6002971_01_gr2.jpg
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ABI-3730 DNA Analyzer (Applied Biosystems, USA) confirmed the case to be compound heterozygote of Hb DIran (beta22 (B4) Glu>Gln; HBB: c.67G>C, GAA>CAA, rs33959855) (Figure 2A) with a beta0-thalassemia mutation [4-base pair (bp) deletion at cds 41/42 (-CTTT)] (Figure 2B). An additional investigation for the XmnI polymorphism and deletional alpha thalassemia revealed that the proband was a homozygote for the wild type allele (CC) in the XmnI locus and heterozygous for the 3.7 kb deletional alpha thalassemia.