Inoue Susumu, Oliveira Jennifer L, Hoyer James D, Sharman Mahesh
Department of Pediatrics, Hurley Medical Center, Flint, Michigan 48503, USA.
Hemoglobin. 2012;36(4):362-70. doi: 10.3109/03630269.2012.679717. Epub 2012 May 7.
Hb Johnstown [β109(G11)Val→Leu, GTG>TTG] has previously been described as a high oxygen affinity variant in a heterozygous state and in combination with β(0)-thalassemia (β(0)-thal). Because the variant does not separate from Hb A by routine methods it may be easily missed unless clinical suspicion is high. Hb Lepore-Boston-Washington (Hb LBW; δ87-β116) is a δβ hybrid variant that clinically manifests similarly to a β(+)-thal. Hb LBW is not detected by routine polymerase chain reaction (PCR) sequencing but is easily detected by electrophoretic methods. We describe a 19-year-old African American male with a compound heterozygosity for Hb Johnstown and Hb LBW. The patient presented with progressively worsening chest pains, headaches and erythrocytosis. He was repeatedly phlebotomized with symptomatic improvement and subsequently was confirmed to have the high oxygen affinity hemoglobin (Hb) variant. The lowest Hb and hematocrit (packed cell volume, PCV) achieved by phlebotomy was 16.1 g/dL and 0.51 L/L, respectively. Currently, he is no longer being phlebotomized, and is feeling relatively well except for minor chest pain. It is unclear to what degree the phlebotomies contributed to his subjective improvement. The combination of Hbs Johnstown and LBW has not been heretofore described, and in this case, was associated with marked symptomatic erythrocytosis. This unique combination results in a more pronounced phenotype, similar to or slightly more severe than, compound Hb Johnstown/β(0)-thal. This compound hemoglobinopathy will likely not be correctly classified using a single method of Hb detection and underscores the need for multiple characterization methods when indicated by the clinical picture.
血红蛋白约翰斯敦[β109(G11)缬氨酸→亮氨酸，GTG>TTG]先前已被描述为一种杂合状态下的高氧亲和力变体，并与β(0) -地中海贫血(β(0) -thal)合并存在。由于该变体通过常规方法无法与血红蛋白A分离，除非临床怀疑度高，否则很容易被漏诊。血红蛋白Lepore -波士顿-华盛顿（血红蛋白LBW；δ87-β116）是一种δβ杂交变体，临床表现类似于β(+) -地中海贫血。常规聚合酶链反应（PCR）测序无法检测到血红蛋白LBW，但通过电泳方法很容易检测到。我们描述了一名19岁的非裔美国男性，他为血红蛋白约翰斯敦和血红蛋白LBW的复合杂合子。患者表现为进行性加重的胸痛、头痛和红细胞增多症。他多次接受放血治疗，症状有所改善，随后被确诊患有高氧亲和力血红蛋白（Hb）变体。放血治疗后达到的最低血红蛋白和血细胞比容（红细胞压积，PCV）分别为16.1 g/dL和0.51 L/L。目前，他不再接受放血治疗，除了轻微胸痛外，感觉相对良好。尚不清楚放血治疗在多大程度上促成了他的主观改善。血红蛋白约翰斯敦和LBW的组合此前尚未见报道，在本病例中，与明显的症状性红细胞增多症相关。这种独特的组合导致了一种更明显的表型，类似于或略重于复合血红蛋白约翰斯敦/β(0) -地中海贫血。使用单一的血红蛋白检测方法可能无法正确分类这种复合血红蛋白病，这突出表明当临床情况表明需要时，需要多种鉴定方法。
