A case with α-thalassemia caused by novel start codon variant in conjunct with right deletion variant of α2-globin gene / 中华医学遗传学杂志

OBJECTIVE@#The explore the genetic basis for a patient with microcytic hypochromic anemia and iron deficiency anemia.@*METHODS@#Common deletions and variants of the globin genes were detected by Gap-PCR and next generation sequencing (NGS). Suspected mutations were verified by Sanger sequencing.@*RESULTS@#Gap-PCR and NGS showed that the proband has carried a αα/-α @*CONCLUSION@#Patients with α HBA2 c.2T>A(p.Met1Lys) α/-α

Analysis of beta-globin gene variants in Liuzhou area of Guangxi / 中华医学遗传学杂志

OBJECTIVE@#To determine the composition and distribution of beta-thalassemia-associated genotypes in Liuzhou area of Guangxi, China.@*METHODS@#From January to December 2017, 13 847 individuals who came for premarital examination, maternity examination or health check were recruited with informed consent. The subjects were analyzed by reverse dot blotting (RDB) for 17 common beta-thalassemia-associated variants among the Chinese population. Individuals with inconsistent results by blood test, electrophoresis, and RDB were subjected to Sanger sequencing to detect rare variants of the beta globin gene.@*RESULTS@#In total 2098 individuals were found to harbor beta-thalassemia-associated variants, which included 2075 heterozygotes (98.90%), 12 compound heterozygotes (0.57%) and 11 homozygotes (0.52%). CD41-42 (48.43%) and CD17 (31.45%) were the most common variants. Three hundred and thirty eight-individuals were found to also carry heterozygous variants of the alpha globin gene, with the most common types being --SEA/aa, -a3.7/aa, aCSa/aa, -a4.2/aa. Through Sanger sequencing, rare genotypes such as beta-32/betaN, betaCD41-42/betaIVS-II-5 and betaCD30/betaN were detected.@*CONCLUSION@#Liuzhou area has a high incidence of beta-thalassemia, but with a complex variant spectrum and clinical phenotypes different from other regions. Genetic counseling and prenatal diagnosis for the carrier population is crucial for the reduction of the related birth defects. Our result may provide valuable information for the prevention and control of beta-thalassemia in this area.

Clinical and genetic analysis of a patient with Hb Ottawa in conjunction with β -thalassemia / 中华医学遗传学杂志

OBJECTIVE@#To analyze the hematological characteristics of a patient with Hb Ottawa in conjunction with β -thalassemia.@*METHODS@#Peripheral blood samples from the proband and her parents were collected and subjected to red blood cell analysis and hemoglobin electrophoresis. Genotypes of α - and β -globin genes were also analyzed.@*RESULTS@#The proband and her mother were both heterozygotes for Hb Ottawa and β -thalassemia variant IVS II-654, and presented with typical β -thalassemia trait featuring hypochromic microcytic anemia. An abnormal hemoglobin band was detected upon electrophoresis.@*CONCLUSION@#Co-existence of Hb Ottawa and β -thalassemia may not aggravate the phenotype.

Rare thalassemia mutations among southern Chinese population / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect rare types of thalassemia mutations among southern Chinese population.</p><p><b>METHODS</b>Peripheral blood samples from 327 patients from various regions of southern China were collected. The patients were suspected as rare-type thalassemia for their inconsistency between hematological phenotypes and results of routine mutation screening. The samples were further analyzed with GAP-PCR and DNA sequencing.</p><p><b>RESULTS</b>One hundred and eight cases were diagnosed as rare types of thalassemia. Among whom 10 rare α-globin gene mutations including --THAI, HKα, αααanti3.7, αααanti4.2, -α2.8, -α27.6, CD74 GAC>CAC (Hb Q-Thailand), CD30 (-GAG), CD31 AGG>AAG and CD118 (+TCA), and 12 rare β-globin gene mutations including CD37 TGG>TAG, CD39 CAG>TAG/CD39 CAG>TAG, β II-2 (-T), -90(C>T), -31(A>C), -88(C>T), CD7(-A), CD138(+T), CD89-93 (--AGTGAGCTGCACTG), CD54-58 (-TATGGGCAACCCT), Chinese G γ +(A γδβ)0 and Vietnamese HPFH (HPFH-6) were identified. -88(C>T) (HBB: c.-138C>T) and CD39 CAG>TAG (HBB: c.118C>T) were discovered for the first time in Chinese population. CD7(-A) (HBB: c.23delA) and CD138(+T) (HBB: c.416_417insT) were new types of β-globin gene mutations.</p><p><b>CONCLUSION</b>The present study have enriched the mutation spectrum of thalassemia in southern China, which has provided necessary information for its diagnosis.</p>

Analysis of clinical phenotype and genotype of unstable Hemoglobin Rush / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the hematological and genetic characteristics of unstable hemoglobin Rush (Hb Rush) and compound heterozygote of Hb Rush and thalassemia.</p><p><b>METHODS</b>Peripheral blood samples and genomic DNA from three patients (including two ethnic Dai and one Han Chinese) with anemia of undetermined origin were collected. Hematological phenotypes of these patients were determined through red blood cell analysis and hemoglobin electrophoresis. Genotypes of alpha- and beta-globin genes, -158 XmnⅠ polymorphic site ofγ promoter region, and haplotypes of 7 polymorphic restriction sites in the beta-globin gene cluster were determined using PCR-based methods and DNA sequencing.</p><p><b>RESULTS</b>All patients have presented hypochromic microcytic anemia and hemoglobin fraction with significant increased measurement (30.5%-59.2%) in the region of fetal hemoglobin during alkaline medium electrophoresis. DNA analysis suggested that all patients have carried mutations leading to the unstable hemoglobin Rush (HBB codon 101, GAG>CAG, Glu>Gln). Two of them were compound heterozygotes of Hb Rush and thalassemia mutations of -α,CD17 and Hb E, respectively. Hb Rush mutation was associated with various haplotypes of the β-globin gene cluster. No significant association was found between increased abnormal hemoglobin fraction in the region of Hb F and the polymorphism ofγ promoter or large deletion of the beta-globin gene cluster.</p><p><b>CONCLUSION</b>This study has confirmed the distribution of Hb Rush among various Chinese populations and is the third report of its kind. Hb Rush can result in increased measurement of hemoglobin fraction in the region of fetal hemoglobin (Hb F) during routine hemoglobin electrophoresis under alkaline condition. Hb Rush heterozygote alone can lead to hypochromic microcytic anemia and thalassemia-like phenotype. Prenatal diagnosis of Hb Rush is necessary for carriers.</p>

Regulación de expresión de genes de la familia de ß-globina humana, útil en la búsqueda de nuevos blancos terapéuticos para tratamiento de hemoglobinopatías / Regulation of the ß-globin gene family expression, useful in the search for new therapeutic targets for hemoglobinopathies

Durante la etapa embrionaria, el desarrollo fetal y la vida posnatal se expresan isoformas funcionalmente distintas de hemoglobina, producto de la combinación de cadenas polipeptídicas sintetizadas a partir de los distintos genes que componen las familias de α- y β-globina. En función de que la presencia de altos niveles de hemoglobina fetal (Hb F) es beneficiosa en síndromes falciformes y talasémicos graves, se plantea revisar las bases de la regulación de la expresión de los genes de la familia de β-globina, en particular los genes que codifican las cadenas de γ-globina (HBG1 y HBG2). En este trabajo se revisan los conocimientos sobre factores de transcripción y reguladores epigenéticos que gobiernan los eventos de encendido y apagado de los genes de la familia de β-globina. Se espera que la consolidación de estos conocimientos permita hallar nuevos blancos terapéuticos para el tratamiento de hemoglobinopatías.

Different hemoglobin isoforms are expressed during the embryonic, fetal and postnatal stages. They are formed by combination of polypeptide chains synthesized from the α- and β- globin gene clusters. Based on the fact that the presence of high hemoglobin F levels is beneficial in both sickle cell disease and severe thalassemic syndromes, a revision of the regulation of the β-globin cluster expression is proposed, especially regarding the genes encoding the γ-globin chains (HBG1 and HBG2). In this review we describe the current knowledge about transcription factors and epigenetic regulators involved in the switches of the β-globin cluster. It is expected that the consolidation of knowledge in this field will allow finding new therapeutic targets for the treatment of hemoglobinopathies.

Analysis of copy number variations in alpha-globin gene in the cases with combined increased levels of HbF with β thalassemia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect copy number changes of α-globin gene, and analyze molecular mechanism of the impacts of fetal hemoglobin (HbF) levels for α-globin gene copy numbers loss or increase.</p><p><b>METHODS</b>A total of 15 cases with combined increased levels of fetal hemoglobin with β-thalassemia were collected. Firstly, three common α-thalassemia deletions were validated by Gap-PCR. Secondly, the largest deletions of the β-globin gene cluster were detected by multiplex ligation-dependent probe amplification (MLPA).</p><p><b>RESULTS</b>Among the 15 cases, there was 1 case with duplication of the α-globin gene cluster, 3 cases of SEA heterozygote deletion of the α-globin gene, 1 cases of α 3.7 deletion heterozygote of the α-globin gene, 1 case of alpha 4.2 deletion homozygote of the α-globin gene, 1 case of deletion homozygote in the like α-globin gene. A compound heterozygous for SEA and α 3.7 of the α-globin gene was also detected. However, 7 cases showed no copy numbers loss and increase of the the α-globin gene cluster.</p><p><b>CONCLUSION</b>Additional α-globin gene can produce excessive α-chain, which can aggravate imbalance for α and β-chain, and cause clinical symptoms in patients with β-thalassemia. Yet, copy number loss or mutation in α-globin gene will cause a milder clinical phenotype.</p>

Prevalence and molecular analysis of α-thalassemia in preschool children in Chongqing city / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the incidence and the gene mutation frequencies and patterns of α-thalassemia in preschool children in Chongqing city.</p><p><b>METHODS</b>Cluster random sampling was used. A total of 1057 preschool children in three areas of Chongqing were screened by using routine blood test and hemoglobin electrophoresis analysis. Molecular analysis carried out for all the samples.</p><p><b>RESULTS</b>Of the 1057 samples, 55 cases were diagnosed as being carriers of α-thalassemia, which included 80 allele genes. Therefore, the frequency of α-thalassemia carriers in Chongqing was 5.20%. Of the 55 α-thalassemia carriers, five different deletions of α-thalassemia were identified, the three most common deletion types and proportions were 54.55% for the -α(3.7) deletion, 18.18% for --(SEA) deletion, and 9.08% for the -α(4.2) deletion, respectively; eight types of nondeletion defects were determined, containing one case of Hb Quong Sze and seven novel mutations of a-globin gene. Furthermore, 24 cases of α-Triplication were detected with the α-Triplication carrier rate of 2.55%. In addition, in this study we also found two cases of abnormal hemoglobin disorders occurred on α-globin gene, Hb J-Wenchang-Wuming and Hb Arya. Hb Arya was characterized in the Chinese population for the first time confirmed by literature retrieval.</p><p><b>CONCLUSION</b>In this study, we have clarified the carrier frequency and molecular spectrum of α-thalassemia in Chongqing, and we first reported the carrier incidence of α-Triplication in Chongqing. The materials obtained from this study would be of valuable reference for genetic counseling and the examination instruction of children in this area.</p>

Hemoglobin Fontainebleau [a21(B2)Ala>Pro]: The second report from India.

Structural hemoglobin (Hb) variants are mainly due to point mutations in the globin genes resulting in single amino acid substitutions. Until date, about 200 alpha chain variants have been identified and they are usually detected during the hemoglobinopathy screening programs. Under a community control program for hemoglobinopathies, which involved screening of antenatal cases followed by prenatal diagnosis if indicated. Here, we report a rare alpha globin gene variant Hb Fontainebleau [a21(B2)Ala>Pro] detected in the heterozygous condition in a 35‑year‑old pregnant lady screened during this program. This is the second report of this alpha globin variant from India. Unlike the earlier case from India where Hb Fontainebleau was reported in a neonate who was also a carrier of Hb Sickle and had no clinical problems, this case presented with a bad obstetric history associated with the secondary infertility. However, the presence of the variant and the obstetric complications may be unrelated.

Clinical Characteristics of Pediatric Thalassemia in Korea: A Single Institute Experience

Few literatures have elaborated on the clinical characteristics of children with thalassemia from low-prevalence areas. A retrospective analysis was conducted on children genetically confirmed with thalassemia at Seoul National University Children's Hospital in Korea. Nine children (1alpha thalassemia trait, 6beta thalassemia minor, 2beta thalassemia intermedia) were diagnosed with thalassemia at median age of 4.3 yr old with median hemoglobin of 9.7 g/dL. Seven (78%) children were incidentally found to be anemic and only 2 with beta thalassemia intermedia had presenting symptoms. Five children (56%) were initially misdiagnosed with iron deficiency anemia. Despite the comorbidities due to alpha thalassemia mental retardation syndrome, the child with alpha thalassemia trait had mild hematologic profile. Children with beta thalassemia intermedia had the worst phenotypes due to dominantly inherited mutations. None of the children was transfusion dependent and most of them had no complications associated with thalassemia. Only 1 child (11%) with codon 60 (T-->A) mutation of the HBB gene needed red blood cell transfusions. He also had splenomegaly, cholelithiasis, and calvarial vault thickening. Pediatricians in Korea must acknowledge thalassemia as a possible diagnosis in children with microcytic hypochromic hemolytic anemia. High level of suspicion will allow timely diagnosis and managements.

[Prevalence of common point mutations of alpha globin gene in Babol, Iran [2005-09]]

Alpha thalassemia is one of the most common hemoglobin disorders. Some combination of alpha globin gene mutations may cause HbH disease with severe anemia or intermediate thalassemia. genotype common deletions are routinely tested for suspicious alpha thalassemia couples but because of lack of information about the nature and frequency of point mutations and higher expenosor of sequencing, less attention was paid to them. This study was done to determine the prevalence of common point mutations of alpha globin gene in Babol, Iran. This descriptive study was carried out on DNA of 153 adult suspected to alpha-thalasemia with deleted alpha-golobolin gene referred to genetic laboratory in Babol, Iran during 2005-09. alpha 1 and alpha 2 genes were amplified by using specific biotinilated primers by PCR method. PCR products were assayed using 11 specific probs corresponding to common point mutations in alpha gene [C19, IVSI [-5nt], C59, Hb constant spring, Hb Icaria, Hb seal Rock, IVSI [148], C14, poly A [-2bp], poly A2, Poly A1] and fixed on byodine C membrabe. Hybridization between the probes and PCR products was visualized after a colorimetric reaction using of conjugated streptavidin peroxidase and TMB [tetra methyle Benzidine] and H[2]O[2]. The prevalence of point mutations in poly A2, 5nt, Hb constant spring and poly A1 were 28.75%, 14.38%, 7.84% and 2.61%, respectively. Point mutation in alpha globin genes was detected in%53.60 out of 153 adults suspected with alpha thalassemia without common deletion mutations

A Case of Heterozygous alpha(+)-Thalassemia Diagnosed in a Korean Family by Using Multiplex Ligation-Dependent Probe Amplification / 임상검사와정도관리

Alpha-thalassemia (alpha-thalassemia), which is prevalent in the Mediterranean region, is caused by deficient synthesis of the alpha-globin chains. It is commonly caused by HBA1 and/or HBA2 gene deletion and is diagnosed by DNA sequence analysis. The proband was a 38-year-old woman who was found to have microcytic and hypochromic anemia on a routine health checkup. Results of the Hb electrophoresis (EP) and direct sequencing of the HBA1 and HBA2 genes were found to be normal. As multiplex ligation-dependent probe amplification (MLPA) for the HBA1 and HBA2 genes revealed heterozygous deletion, she was diagnosed with heterozygous alpha+-thalassemia. Although routine laboratory tests revealed similar findings in the proband's father, brother and niece, MLPA revealed heterozygous deletions of the HBA1 or HBA2 gene in her brother and niece. In summary, we report a case of heterozygous alpha+-thalassemia in a Korean family that was detected by MLPA. We recommend that patients with suspected hemoglobinopathies should be followed-up further with MLPA, especially when Hb EP shows a normal pattern.

Characterization of alpha thalassemic genotypes by multiplex ligation-dependent probe amplification in the Brazilian population

Alpha-thalassemia is the most common inherited disorder of hemoglobin synthesis. Genomic deletions involving the alpha-globin gene cluster on chromosome 16p13.3 are the most frequent molecular causes of the disease. Although common deletions can be detected by a single multiplex gap-PCR, the rare and novel deletions depend on more laborious techniques for their identification. The multiplex ligation-dependent probe amplification (MLPA) technique has recently been used for this purpose and was successfully used in the present study to detect the molecular alterations responsible for the alpha-thalassemic phenotypes in 8 unrelated individuals (3 males and 5 females; age, 4 months to 30 years) in whom the molecular basis of the disease could not be determined by conventional methods. A total of 44 probe pairs were used for MLPA, covering approximately 800 kb from the telomere to the MSLN gene in the 16p13.3 region. Eight deletions were detected. Four of these varied in size from 240 to 720 kb and affected a large region including the entire alpha-globin gene cluster and its upstream regulatory element (alpha-MRE), while the other four varied in size from 0.4 to 100 kb and were limited to a region containing this element. This study is the first in Brazil to use the MLPA method to determine the molecular basis of alpha-thalassemia. The variety of rearrangements identified highlights the need to investigate all cases presenting microcytosis and hypochromia, but without iron deficiency or elevated hemoglobin A2 levels and suggests that these rearrangements may be more frequent in our population than previously estimated.

Detection of common deletions and mutations causing α-thalassemia in Southeast Asians and Southern Chinese with denaturing high performance liquid chromatography / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To establish a comprehensive and simple assay using denaturing high performance liquid chromatography (DHPLC) for the diagnosis of most common mutations and deletions of α-thalassemia gene in Southeast Asians and Southern Chinese.</p><p><b>METHODS</b>This assay has included a duplex polymerase chain reaction (PCR) followed by DHPLC analysis. An improved PCR was also performed followed by DHPLC analysis. With this assay, a blinded study of 160 samples was screened for three common mutations and three common deletions.</p><p><b>RESULTS</b>The duplex PCR-DHPLC combined with the improved PCR-DHPLC analysis has detected all mutations and the wild-type allele. The results were consistent with those by the original methods.</p><p><b>CONCLUSION</b>This molecular assay may be used for the diagnosis of α-thalassemia patients from this geographical region. The method is accurate, rapid, semi-automatic and cost-effective, which makes it suitable for large-scale screening.</p>

Microcytic hypochromic anemia patients with thalassemia: genotyping approach.

BACKGROUND: Microcytic hypochromic anemia is a common condition in clinical practice, and alpha-thalassemia has to be considered as a differential diagnosis. AIMS: This study was conducted to evaluate the frequency of alpha-gene, beta-gene and hemoglobin variant numbers in subjects with microcytic hypochromic anemia. SETTING AND DESIGNS: Population-based case-control study in the Iranian population. MATERIALS AND METHODS: A total of 340 subjects from southwest part of Iran were studied in the Research Center of Thalassemia and Hemoglobinopathies (RCTH), Iran. Genotyping for known alpha- and beta-gene mutations was done with gap-PCR and ARMS. In cases of some rare mutations, the genotyping was done with the help of other techniques such as RFLP and ARMS-PCR. STATISTICAL ANALYSIS: Statistical analysis was carried out by SPSS 11.5 and an independent-sample t test. RESULTS: Out of the total 340 individuals, 325 individuals were evaluated to have microcytic hypochromic anemia based on initial hematological parameters such as MCV<80 fl; MCH<27 pg; the remaining 15 patients were diagnosed with no definite etiology. The overall frequency of -alpha3.7 deletion in 325 individuals was 20.3%. The most frequent mutations were IVS II-I, CD 36/37 and IVS I-110 with frequencies of 6.31%, 5.27% and 1.64%, respectively. Only, there was a significant difference between beta-thalassemia trait and beta-thalassemia major with regard to MCV (P<0.05) and MCH (P<0.05) indices, and also MCH index between beta-thalassemia trait and Hb variants (P<0.05). CONCLUSION: Molecular genotyping provides a rapid and reliable method for identification of common, rare and unknown alpha- and beta-gene mutations, which help to diagnose unexplained microcytosis and thus prevent unnecessary iron supplementation.

The regulation effect of liposomal transfection of antisense oligonucleotide on the alpha-globin in patients with severe beta-thalassemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the effect of liposomal transfection of antisense oligonucleotide (ASON) on the erythroid cell alpha-globin gene in the patients with severe beta-thalassemia, and provide a new idea for beta-thalassemia gene therapy.</p><p><b>METHODS</b>A highly effective ASON targeting alpha-globin gene was transfected into severe beta-thalassemic erythroid cells cultured in vitro by liposomal at an optimal concentration. The expression level of alpha, beta, gamma-globin gene, the level of hemoglobin, and the excess alpha-globin chains precipitates in ASON group and control group were carefully analyzed by quantitative real-time PCR(Q-RT-PCR), high performance liquid chromatography (HPLC), and electron microscope, respectively.</p><p><b>RESULTS</b>The mRNA expression of alpha-globin gene was significantly lower in ASON group (9.04 +/- 0.29) than in control group (24.23 +/- 0.29) (P<0.01). Simultaneously, the disequilibrium between alpha- and beta-, gamma-globin gene expression was partly modified by ASON, the ratios of ASON group and control group being 0.79 +/- 0.02 and 2.26 +/- 0.06 respectively (P<0.01). HPLC demonstrated that the levels of HbA2 and HbF increased with downregulation of alpha-globin gene in beta-thalassemic erythroid cells, particularly HbF. The precipitates of alpha-globin chains in ASON group were lessened under electron microscope, particularly in early erythroblast while no change in the control group.</p><p><b>CONCLUSION</b>The high effective ASON contributes to inhibit the alpha-globin gene expression of severe beta-thalassemic erythroid cells, partly modify the disequilibrium between alpha-, beta- and gamma-globin gene expression and obviously reduce the precipitates of alpha-globin chains in erythroid cells. It might provide a new idea for gene therapy of beta-thalassemia.</p>

Detection and identification of specific serum biomarkers in papillary thyroid cancer / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To detect and identify the potential specific serum biomarkers for diagnosis of papillary thyroid cancer.</p><p><b>METHODS</b>Samples of 35 patients with papillary thyroid carcinoma, 40 patients with benign thyroid nodule and 34 healthy individuals were analyzed using the SELDI-TOF ProteinChip System and bioinfomation technology to find the differential peaks which were separated by HPLC and then further analyzed by LC-MS/MS. The protein sequences were analyzed by SEQUEST software and searched in Bioworks database.</p><p><b>RESULTS</b>The top six mass-to-charge ratio (M/Z) peaks with the smallest P value were 6651, 6452, 7653, 7932, 15 106 and 15 848 Da, respectively. The 6651 and 6452 Da proteins were weakly expressed in papillary thyroid carcinoma but highly expressed in benign thyroid nodules and healthy individuals. The differences had statistical significance (P < 0.01). The 7653, 7932, 15 106, 15 848 Da proteins were highly expressed in papillary thyroid carcinoma but weakly expressed in benign thyroid nodules and healthy individuals. The differences were statistically significant (P < 0.01). Combination of these six proteins, using the method of leave-one-out to make crossing detection, the specificity of discriminating papillary thyroid carcinoma and non-cancer was 88.0%, and its sensitivity was 92.5%. The 6651 and 6452 Da proteins were identified as apolipoprotein C-I and apolipoprotein C-III, respectively. The 7653 and 15 106 Da proteins were identified as the same protein-alpha-globin, and the 7932 and 15,848 Da proteins were identified as the same protein-beta-globin.</p><p><b>CONCLUSION</b>The detection of differentially expressed apolipoprotein C-I, apolipoprotein C-III, alpha-globin, and beta-globin may have utility for diagnosis of papillary thyroid carcinoma and are worthy of further investigation.</p>

Successful preimplantation genetic diagnosis of Hb Bart's hydrops fetalis in Singapore after fresh and frozen embryo replacement cycles

<p><b>INTRODUCTION</b>We report the fi rst successful preimplantation genetic diagnosis (PGD) for Hb Bart's hydrops fetalis in Singapore, involving both fresh and frozen embryo replacement cycles.</p><p><b>CLINICAL PICTURE</b>Two couples who were carriers of the Southeast Asian type double gene deletion (--(SEA) deletion carriers) requested for PGD. Couple A had 2 previous affected pregnancies, while couple B have a child of unknown genotypic status.</p><p><b>TREATMENT</b>One PGD cycle was performed for each couple. The --(SEA) deletion was detected using a gap-PCR strategy. Couple A had 1 fresh-embryo replacement cycle while couple B underwent 2 frozen-embryo replacement cycles.</p><p><b>OUTCOME</b>Couple A achieved a twin pregnancy. Second trimester complications resulted in premature delivery, where 1 baby girl survived. Couple B achieved a singleton pregnancy resulting in delivery of a healthy baby boy. Genotype analysis of all babies confirmed the PGD results consistent with clinically unaffected status.</p><p><b>CONCLUSIONS</b>We have successfully performed PGD to avoid Hb Bart's hydrops fetalis syndrome.</p>

Effect of liposomal transfection of antisense oligodeoxynucleotide on alpha-globin gene expression and proliferation of K562 cells / 中国实验血液学杂志

The objective of study was to investigate the effect of liposomal transfection of antisense oligodeoxynucleotide (ASON) on alpha-globin gene expression and proliferation of K562 cells, to explore the new way of gene therapy in beta-thalassemia. Targeted ASON of alpha-globin was designed and synthesized, and compared with positive control [sense oligodeoxynucleotide (SON) group] and blank control. By liposomal transfection, ASON, SON was co-cultured with K562. The efficiency of transfection was assayed by fluorescence microscopy and flow cytometry (FCM), the alpha-globin gene expression of K562 was measured by real-time PCR, and the proliferation of K562 was determined by Cell Count Kit-8 assay. The results indicated that the highest efficiency was at 24 hours after liposomal transfection, the gene expression level of alpha-globin in ASON group was significantly lower than that in SON group and blank control (p < 0.01). The proliferation of K562 cells was obviously inhibited, meanwhile the above effect showed the dose-dependent manner. It is concluded that the liposomal transfection of ASON inhibits the alpha-globin gene expression of K562 cells, which may be the new target for gene therapy in beta-thalassemia.

Change of the chromosome conformation of human alpha-globin gene locus in transgenic mice / 中国医学科学院学报

<p><b>OBJECTIVE</b>To establish chromosome conformation capture (3C) strategy and to use this method for exploring the effect of chromosome conformation on human alpha-globin gene expression in the human alpha-globin transgenic mouse.</p><p><b>METHODS</b>Homozygous human alpha-globin transgenic male mouse was crossed with KM female mouse. The 14.5-day post-coitum (dpc) embryos were used for the isolation of fetal liver and fetal brain cells. Homogeneous single-cell suspension was treated with formaldehyde to crosslink the chromatin conformation in the nuclear. The cross-linked chromatin compound was digested with Nco I and then ligated with T4 DNA ligase. The ligated compound was reversely cross-linked and then the ligated genomic DNA was purified for PCR analysis. The primers were designed along the two sides of cut and ligated sites. Semi-quantitative PCR was used to analyze the chromosome conformation of the whole human alpha-globin gene locus in fetal liver and fetal brain cells.</p><p><b>RESULTS</b>When HS40 fragment was used as the fixed fragment, in fetal brain cells, the ligation frequencies of HS40 fragment with other fragments were decreased as the linear distances to HS40 fragment were increasing; while in fetal liver cells, two active genes (alpha1 and alpha2) fragments showed higher ligation frequencies with HS40 fragment than other fragments. However, the fragment containing an inactive gene (xi) displayed the comparable low ligation frequency as that in fetal brain. When alpha2 fragment was used as the fixed fragment, similarly, in fetal brain cells the ligation frequencies of alpha2 fragment with other ones were decreased as the linear distances increasing; when in fetal liver cells, it showed higher ligation frequencies with two upstream regulatory elements (HS 40 and 33). However, it showed a little bit lower ligation frequency with another two upstream regulatory elements (HS10 and 8) than those in fetal brain.</p><p><b>CONCLUSION</b>In fetal liver cells, the distant regulatory elements are in close proximity to the downstream of the expressed globin genes through looping out, the interval region; however, in fetal brain, they were not in vicinity to the expressed globin genes.</p>