Fucharoen Goonnapa, Fucharoen Supan, Singsanan Sanita, Sanchaisuriya Kanokwan
Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.
Am J Hematol. 2007 May;82(5):381-5. doi: 10.1002/ajh.20818.
We describe hematological and molecular characterization of a Thai female who had Southeast Asian ovalocytosis (SAO) associated with beta+-thalassemia trait. The proband had mild microcytosis with Hb 12.9 g/dl, Hct 35.8%, MCV 74.4 fl, MCH 26.8 pg, MCHC 36.0 g/dl, and elevated Hb A2 (5.6%), characteristics of beta-thalassemia trait. Peripheral blood film examination revealed prominent ovalocytosis. However, a one-tube osmotic fragility (OF) test commonly used for thalassemia screening was negative and a normal OF curve was observed. Further polymerase chain reaction (PCR) analyses identified the beta(-28A-G) mutation in the beta-globin gene and a 27 bp deletion in erythrocyte band 3 protein gene, indicating a genetically compound heterozygote. Hematological data of the proband was comparatively presented with those of eight female and 15 male carriers of pure beta-thalassemia with the same mutation. The finding demonstrates that although the association of the SAO and beta-thalassemia does not produce a more severe clinical picture, this could lead to a mis-screening of beta-thalassemia using an OF test as a primary screening test. Additional blood film examination followed by PCR could help in the detection of this unusual genetic interaction in the region.
我们描述了一名患有东南亚椭圆形红细胞增多症（SAO）并伴有β+地中海贫血特征的泰国女性的血液学和分子特征。先证者有轻度小红细胞症，血红蛋白为12.9 g/dl，血细胞比容为35.8%，平均红细胞体积为74.4 fl，平均红细胞血红蛋白含量为26.8 pg，平均红细胞血红蛋白浓度为36.0 g/dl，且血红蛋白A2升高（5.6%），这些都是β地中海贫血特征的表现。外周血涂片检查显示有明显的椭圆形红细胞增多。然而，常用于地中海贫血筛查的单管渗透脆性（OF）试验呈阴性，观察到正常的OF曲线。进一步的聚合酶链反应（PCR）分析确定了β珠蛋白基因中的β（-28A-G）突变以及红细胞带3蛋白基因中的27 bp缺失，表明为遗传复合杂合子。将先证者的血液学数据与八名女性和十五名男性携带相同突变的纯β地中海贫血携带者的数据进行了比较。该发现表明，虽然SAO与β地中海贫血的关联不会产生更严重的临床表现，但这可能导致使用OF试验作为初步筛查试验时对β地中海贫血的误筛。随后进行PCR的额外血涂片检查有助于检测该地区这种不寻常的基因相互作用。
