深圳地区12960例地中海贫血筛查受检者的地中海贫血基因型分析

目的 探讨深圳地区地中海贫血基因型特征,及其罕见基因型碱基突变位点.方法 选择2014年5月至2015年10月于广东省深圳市第二人民医院拟行地中海贫血筛查的12 960例受检者为研究对象.研究对象纳入标准:①红细胞平均体积(MCV)＜80 fl的门诊及住院患者;②于本院行产前筛查的孕妇.排除标准:①不愿意参加本试验者;②已被确诊为其他血液系统疾病者.受试者先进行血常规MCV、血红蛋白(Hb)电泳和红细胞脆性检测的地中海贫血筛查试验,对筛查试验阳性(红细胞脆性＜70％)的患者,采用跨越断裂点PCR及反向斑点杂交(RDB)技术进行地中海贫血基因常见缺失型和点突变的基因型检测.对常见基因型检测不能确诊的患者,采用巢式PCR和PCR-直接测序(SBT)技术进行罕见基因型分析.本研究遵循的程序符合深圳市第二人民医院制定的伦理学标准,得到该委员会批准,并征得受试对象本人的知情同意,与之签署临床研究知情同意书.结果 12 960例受检者中,地中海贫血筛查试验阳性患者为2 194例,通过常见基因型检测,确诊1 019例为地中海贫血,检出率为46.4％.537例α地中海贫血患者中,以东南亚缺失型(--SEA/αα)比例最高,占66.1％(355/537),其次为α地中海贫血2(-α 3.7/αα)占15.6％(84/537),而基因型(αCS α/αCSα、αQS α/αQS α、αWS α/αWSα)和4种HbH病基因型(-α3.7/αQS ααQS、--SEA /αCS αCS、--SEA/αQS αQS、--SEA/αWS αWS)较为少见.α地中海贫血罕见基因型检出率为0.1％(3/2 194),包括2例HKαα/--SEA及1例HKαα/αα.在456例β地中海贫血患者中,β41-42(-TCTT)/β和β654(C＞T) /βA基因型检出率最高,分别为33.8％(154/456)和30.3％(138/456).在26例β复合α地中海贫血患者中,以β复合α地中海贫血1(--SEA/αα)基因型检出率最高(34.6％,9/26).β地中海贫血罕见基因型检出率为0.2％(4/2 194),包括2例β37G＞A),突变点为413 G＞A或405 G＞A,1例β88-93(-AGTG),突变点为557处出现杂合峰,1例β-88(C＞T),突变点为-88 C＞T.结论 深圳地区地中海贫血基因型有独特的分布特征,巢式PCR技术有助于发现HKαα/--SEA及HKαα/αα基因型.采用PCR-SBT技术能鉴定罕见地中海贫血基因型并发现新突变点.本研究结果为在深圳地区开展遗传咨询和产前诊断提供了参考数据.     

Heavy metal levels in patients with ineffective erythropoiesis

Objectives

Iron is taken into enterocytes at the duodenum via apical divalent metal-ion transporter 1 protein. Besides iron, divalent metal-ion transporter 1 also transports other divalent metals. We aimed to investigate blood heavy metal levels in patients with ineffective erythropoiesis.

地中海贫血患者心肌、肝脏铁沉积与血清铁蛋白相关性研究

目的定量评价地中海贫血患者心脏和肝脏铁过载,探讨心脏、肝脏铁沉积与血清铁蛋白(SF)相关性。材料与方法应用3.0 T磁共振扫描基因确诊地中海贫血患者134例(包括中间型73例和重型61例),扫描包括:肝脏冠状面T2WI及横断面T1WI、T2WI、12回波梯度回波(T2*)序列;心脏标准横断面T2WI及两腔位、四腔位及短轴面电影和8回波梯度回波(T2*)成像。测量心肌、肝脏T2*值,所有受试者MRI扫描前1周完成SF检测。采用Spearman秩相关分析心肌、肝脏铁沉积和SF三者间相关性。结果 134例地中海贫血患者心肌T2*、肝脏T2*、SF中位数分别为23.35(1.88~36.17)ms、1.33(0.36~16.39)ms、1235.3(105.1~14673.0)μg/L,心肌-肝脏T2*(r_s=0.324,P=0.000)、心肌T2*-SF(r_s=-0.491,P=0.000)、肝脏T2*-SF(r_s=-0.697,P=0.000)具有一定相关性。73例中间型地中海贫血患者心肌T2*、肝脏T2*、SF中位数分别为26.18(7.09~36.17)ms、1.81(0.37~16.39)ms、622.8(105.1~10807.0)μg/L,心肌-肝脏T2*(r_s=0.059,P=0.619)、心肌T2*-SF(rs=-0.166,P=0.161)无明显相关,但肝脏T2*-SF间中度负相关(r_s=-0.583,P=0.000)。61例重型地中海贫血患者心肌T2*、肝脏T2*、SF中位数分别为18.80(1.88~33.11)ms、0.72(0.36~10.36)ms、3310.0(313.0~14673.0)μg/L,心肌-肝脏T2*(r_s=0.365,P=0.004)、心肌T2*-SF(r_s=-0.359,P=0.004)、肝脏T2*-SF(r_s=-0.707,P=0.000)具有轻中度相关性。结论在一定范围内,地中海贫血患者心铁沉积与肝铁含量、SF具有较低或无相关性,其间相关性可能随病情加重而增加,而肝铁过载则与SF中度负相关。     

广西南宁农村育龄地中海贫血高危孕妇产前诊断分析

目的探索适用于在农村推广的地中海贫血（地贫）干预模式。方法依托计划生育系统,跟踪高危地贫夫妇,176对前期筛查出的高危夫妇已经妊娠者纳入研究。结果 176例孕妇中,25例孕妇失去联系,2例拒绝行产前诊断。其余149例,重型或中间型β地贫6例,重型α地贫4例,中间型α地贫（HbH病）15例,HbH病复合轻型β地贫1例;轻型（或静止型）α或β地贫或轻型（或静止型）α合并β地贫86例,正常37例。HbH病胎儿中,非缺失型（HbH-CS）5例,其余为缺失型HbH病。26例确诊重型或中间型α或β地贫者均终止妊娠。结论依托计划生育部门主动服务,是在农村开展地贫干预的适宜措施。     

离子交换高效液相色谱法血红蛋白分析筛查地中海贫血的研究

目的探讨离子交换高效液相色谱法（HPLc）血红蛋白分析用于地贫筛查的应用价值和基本规律。方法收集50例血常规表型正常、151例小细胞低血素症外周全血,及7例含Hb变异体的α-地贫外周全血或脐带血标本,用VARIANTTMⅡ离子交换HPLCHb分析系统及配套β-地贫短程序试剂进行Hb组分分析,再根据Hb分析及DNA分子诊断结果分组统计和全面评价。结果50例正常标本HbA．2．0％～4．0％、HbF〈2．0％。151例小细胞低血素症标本中,40例HbA,〉4．0％、HbF〈5．0％的标本均确诊为p一地贫基因携带者,筛查符合率100％109例HbA,〈4．0％、HbF〈2．0％的标本中确诊108例为α-地贫;2例HbA．〈4．0％、HbF≥5．0％的标本分别确诊为δβ-地贫和HPFH。HPLC图谱显示能检出但不能定量的Hb变异体为HbH、HbBart’s和HbCS,不能检出HbWS。结论离子交换HPLCHb分析操作简单,结果稳定可靠,人为因素影响小,适合大规模人群筛查及常规检测;并提示实践应用中,须注意特定仪器及配套试剂所采用技术的适应范围,总结经验,丰富及完善其分析数据库及色谱图,避免误诊和漏检。     

广西柳州地区αβ复合型地中海贫血基因突变类型及检出率分析

目的研究广西柳州地区αβ复合型地中海贫血（地贫）基因突变类型及检出率。方法采用膜反向杂交技术检测β地贫基因。用gap-PCR法检测三种常见α地贫缺失基因型：东南亚型缺失（--SEA）、右侧缺失（-α^3.7）、左侧缺失（-α^4.2）。结果153例β地贫中检测出30名α地贫,检出率为19.61%。均为轻型β地贫复合α地贫,其中β地贫杂合子复合--SEA/αα占90.00%,β地贫杂合子复合-α^3.7/αα占3.33%,β地贫杂合子复合-α^4.2/αα占6.67%。结论广西柳州地区αβ复合型地贫检出率高。--SEA/αα是本地区β地贫杂合子检出的主要复合α地贫基因型。准确诊断β地贫合并α地贫双重杂合子对正确进行遗传咨询,搞好优生优育十分重要。     

Molecular characterization and origins of Hb Constant Spring and Hb Paksé in Southeast Asian populations

Hemoglobin Constant Spring (Hb CS) and Hb Paksé, two abnormal Hbs characterized by elongated α-globin chains resulting from mutations of the termination codon in the α2-globin gene, are the most prevalent nondeletional α-thalassemias in Southeast Asia. To determine the origins of these two variants in the region, we have determined α-globin gene haplotypes associated with these two variants on 120 Thai, eight Cambodian, and six Laos alleles, and the results were compared with those reported previously for the Chinese and Mediterranean. Five haplotypes were found to be associated with 131 α^CS genes examined, whereas a single haplotype was linked to all the α^Paksé genes in these Southeast Asian populations. All the α^CS haplotypes differed from those of the Mediterranean, but one of them was similar to a Chinese α^CS gene reported previously. It is concluded that there are multiple origins of the α^CS and a single origin of the α^Paksé mutations in Southeast Asia. Hematological findings confirm the mild thalassemia intermedia phenotypes for pure homozygous Hb CS and homozygous Hb CS with Hb E heterozygote and Hb E homozygote. The appearance of Hb CS peak by high-performance liquid chromatography analysis indicates the ability to form a tetrameric Hb molecule between the α^CS and β^E chains, leading to a novel derivative with similar characteristics to Hb CS.     

Bone marrow changes in beta-thalassemia major: quantitative MR imaging findings and correlation with iron stores

The purpose of this study is to describe the MR imaging features of bone marrow in beta-thalassemia major and investigate their relation to ferritin, liver and spleen siderosis. Spinal bone marrow was prospectively assessed on abdominal MR studies of 40 transfused beta-thalassemic patients and 15 controls using T1-w, Pd, T2*-w Gradient Echo (GRE) and T1-w turbo Spin Echo (TSE) sequences. Signal intensity (SI) ratios of liver, spleen and bone marrow to paraspinous muscles (L/M, S/M, B/M respectively) and the respective T2 relaxation rates (1/T2) were calculated. Serum ferritin levels were recorded. Bone marrow hypointensity in at least T2*-w GRE sequence was noted in 29/40 (72.5%) patients. Eleven/40 patients exhibited normal B/M on all MR sequences. Five/40 patients had normal B/M and low L/M. B/M correlated with L/M in T1-w TSE sequence only (r = 0.471, p = 0.05). B/M correlated with S/M and mean ferritin values in all sequences (r > 0.489, p < 0.01 and r  >  − 0.496, p < 0.03 respectively). Marrow 1/T2 did not correlate with ferritin values or liver and spleen 1/T2. B/M in transfused beta-thalassemic patients is related to splenic siderosis and ferritin levels. Although marrow is usually hypointense, it may occasionally display normal SI coexisting with liver hypointensity, a pattern typical of primary hemochromatosis.     

G6PD缺乏对地中海贫血产前筛查血液学指标的影响

目的探讨葡萄糖6磷酸脱氢酶（G6PD）缺乏对地中海贫血基因携带者平均红细胞容积（MCV）、红细胞平均血红蛋白含量（MCH）的影响。方法2006-06—2008—12产前筛查的孕妇及其丈夫中行地中海贫血基因分析确诊为地中海贫血基因携带者,常规行C6PD酶活性测定及血细胞分析。分为C6PD缺乏组及G6PD正常组,比较两组的MCV、MCH。结果α地贫-1合并G6PD缺乏组MCV、MCH显著高于α地贫-1不合并C6PD缺乏组（P〈0．05）,轻型β地贫合并G6PD缺乏组MCV显著高于轻型β地贫不合并G6PD缺乏组（P〈0．05）,轻型β地贫合并G6PD缺乏组MCH高于轻型β地贫不合并G6PD缺乏组,但差异无统计学意义。结论G6PD缺乏可影响MCV、MCH筛查地贫的敏感性而造成漏诊,因此建议常规应用血细胞分析、血红蛋白电泳、红细胞渗透脆性联合筛查地中海贫血,并同时检测G6PD活性,以提高地贫基因携带者的检出率,减少出生缺陷。     

桂林市城镇育龄人群地中海贫血现况调查

目的 调查桂林市城镇育龄人群地中海贫血(地贫)的现况.方法 用红细胞平均容积(MCV)和血红蛋白电泳法对所有调查对象进行地贫筛查,对筛查出疑为α地贫或β地贫标本进一步采用PCR结合反向点杂交法(ROB)进行基因检测,以检出地贫基因来确诊.结果 在1580例受检者中,确定α地贫基因型的有79例,检出率为5.00%,α贫在男女性中检出率分别为5.32%、4.68%,差异无统计学意义(X2=3.04,X2＜X0.05(1)=3.84,P＞0.05);确定β地贫基因型的有114例,检出率为7.22%,β地贫在男女性中检出率分别为7.85%、6.58%,差异无统计学意义(X2=0.95,X2＜X0.05(1)=3.84,P＞0.05);总的地贫检出率为12.22%(193/1580).α地贫共检出10种基因型,以轻型--SEA/αα为主,检出率为3.54%;静止型以-α3.7/αα居多,轻型以--SEA/αα居多,中间型以--SEA/-αCS居多;其构成比分别为7.59%、70.88%、2.53%;B地贫共检出7种基因型,以CD41-42(-TTCT)居多,检出率为3.16%,其中最常见的3种基因型CD41-42(-TTCT)、CDl7(A→T)和IVS-Ⅱ-654(C→T),构成占突变基因的87.71%;β、α复合型地贫检出率为0.63%.结论 桂林市城镇育龄人群地贫检出率较高.