Pornprasert Sakorn, Panyasai Sitthichai, Kongthai Kanyakan, Treesuwan Kallayanee
Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang-Mai University, 110 Intawaroros Road, Chiang-Mai, Thailand.
Hemoglobin. 2012;36(3):265-9. doi: 10.3109/03630269.2012.669358. Epub 2012 Apr 3.
Hb S [β6(A3)Glu→Val, GAG>GTG] is a β-globin gene variant that has a very low incidence in the Thai population. Coinheritance of Hb S and β(0)-thalassemia (β-thal) can result in severe clinical conditions. This study reports the case of a Thai patient with a compound heterozygosity for Hb S and β(0)-thal codon 17 (A>T). His hemoglobin (Hb), hematocrit (packed cell volume, PCV), mean corpuscular volume (MCV) and mean corpuscular Hb (MCH) levels were all less than the lower limits, while red cell distribution width (RDW) was higher than the upper limit. Levels of Hbs S, F and A(2) detected by high performance liquid chromatography (HPLC) were comparable to those from capillary electrophoresis (CE). As Hb S has a similar electrophoretic mobility and the HPLC profile is also similar to those of Hb Tak [β147, Term→Thr (+AC)] and Hb D-Punjab [β121(GH4)Glu→Gln, GAA>CAA], DNA sequencing was then performed. This was to detect β(0)-thal, and to differentiate Hb S from the Hb Tak and Hb D-Punjab mutations. The β(0)-thal codon 17 and Hb S mutations were detected indicating that coinheritance of these two mutations can be found in the Thai population. Therefore, to provide proper clinical management and genetic counseling of this rare case, DNA analysis should be performed in all cases when a peak at the S-window is detected by HPLC or CE.
血红蛋白S [β6(A3)谷氨酸→缬氨酸，GAG>GTG] 是一种β-珠蛋白基因突变体，在泰国人群中发病率极低。血红蛋白S与β(0)-地中海贫血（β-地贫）的共同遗传可导致严重的临床病症。本研究报告了一名泰国患者的病例，该患者为血红蛋白S和β(0)-地贫密码子17（A>T）的复合杂合子。其血红蛋白（Hb）、血细胞比容（红细胞压积，PCV）、平均红细胞体积（MCV）和平均红细胞血红蛋白（MCH）水平均低于下限，而红细胞分布宽度（RDW）高于上限。通过高效液相色谱法（HPLC）检测的血红蛋白S、F和A(2)水平与毛细管电泳法（CE）检测的结果相当。由于血红蛋白S具有相似的电泳迁移率，且HPLC图谱也与血红蛋白Tak [β147，末端→苏氨酸（+AC）] 和血红蛋白D-旁遮普 [β121(GH4)谷氨酸→谷氨酰胺，GAA>CAA] 的图谱相似，因此随后进行了DNA测序。这是为了检测β(0)-地贫，并将血红蛋白S与血红蛋白Tak和血红蛋白D-旁遮普突变区分开来。检测到了β(0)-地贫密码子17和血红蛋白S突变，表明在泰国人群中可发现这两种突变的共同遗传。因此，为了对这一罕见病例进行适当的临床管理和遗传咨询，当通过HPLC或CE在S窗口检测到峰值时，所有病例均应进行DNA分析。
