Comparison of the characteristics of two hemoglobin variants, Hb D-Iran and Hb E, eluting in the Hb A2 window

BACKGROUND: Cation exchange-high performance liquid chromatography (CE-HPLC) is most commonly used to evaluate hemoglobin (Hb) variants, which elute in the Hb A2 window. This study aimed to assess prevalence of an uncommon Hb variant, Hb D-Iran, and compare its red cell parameters and peak characteristics with those of Hb E that commonly elutes in the Hb A2 window. METHODS: Generally, we assess abnormal Hb using CE-HPLC as the primary technique along with alkaline and acid electrophoresis. All cases with Hb A2 window >9%, as assessed by CE-HPLCs during 2009–2013, were selected. RESULTS: Twenty-nine cases with Hb D-Iran variant were identified—25 heterozygous, 2 homozygous, 1 compound heterozygous Hb D-Iran/β-thalassemia, and 1 Hb D-Iran/Hb D-Punjab. Overall prevalence of Hb D-Iran was 0.23%. Compared to patients with Hb E, those with Hb D-Iran had significantly higher Hb (12.1 vs. 11.3 g/dL, P=0.03), MCV (82.4 vs. 76.4 fL, P=0.0044), MCH (27.9 vs. 25.45 pg, P =0.0006), and MCHC (33.9 vs. 33.3 g/dL, P=0.0005). Amount of abnormal Hb (40.7 vs. 26.4%, P=0.0001) was significantly higher while retention time (3.56 vs. 3.70 min, P=0.0001) was significantly lower in Hb D-Iran than in Hb E. CONCLUSION: Hb D-Iran peak can be easily missed if area and retention time of the Hb A2 window are not carefully analyzed. To distinguish between variants, careful analysis of peak area and retention time is sufficient in most cases and may be further confirmed by the second technique—alkaline electrophoresis.

JAK2 mutation-negative essential thrombocythemia in a child presenting with cerebral venous thrombosis

Essential thrombocythemia [ET] is a rare myeloproliferative disorder occurring predominantly in the elderly population. Its occurence in the pediatric age group is even more rare. We report a 1 3-year-old girl who presented with isolated cerebral venous thrombosis and was diagnosed with essential thrombocythemia. Family screening for any thrombocytosis was 20 negative. With no secondary cause apparent for persistent thrombocytosis, we looked for the JAK2 mutation, but the result was negative. In contrast to linkage of JAK2 mutation positivity with increased thrombotic risk, our case showed that thrombosis can occur in the absence of JAK2 mutation in a case of essential thrombocythaemia. The indications for treatment and the best treatment of children with ET are currently not known, and guidelines for the management of children with ET are needed. Adult patients have near-normal life expectancy because of the low rate of leukemic conversion, but no child has been monitored long enough to assess prognosis