Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 661
Filtrar
1.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 28(6): 2028-2032, 2020 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-33283737

RESUMO

OBJECTIVE: To analyze the hematological characteristics of Hb Broomhill and Hb Hornchurch, and prenatal diagnosis should be carried out in two families. METHODS: RBC parameters and hemoglobin electrophoretogram were analyzed on the peripheral blood of all patients, and amniotic fluid was collected for prenatal diagnosis. PCR-Flow fluorescent hybridization and Sanger sequencing were performed for gene diagnosis of thalassemia. RESULTS: Three cases of Hb Broomhill were detected, including 2 cases with common SEA α-thalassemia, which was characterized by hypochromic microcytic mild anemia, the capillary electrophoregram revealed a tiny shoulder peak before the Hb A peak; 1 case was diagnosed as Hb Hornchurch combined with ß-thalassemia, which also showed mild anemia. Hemoglobin electrophoretogram showed an abnormal hemoglobin variant peak at Hb A2 zone. CONCLUSION: The carriers of Hb Broomhill and Hb Hornchurch do not have microcytic hypochromic anemia, which do not aggravate the hematological symptoms, such as anemia when being combined with thalassemia of the same type.


Assuntos
Anemia Hipocrômica , Hemoglobinas Anormais , Talassemia alfa , Talassemia beta , Hemoglobinas Anormais/genética , Heterozigoto , Humanos , Talassemia alfa/diagnóstico , Talassemia alfa/genética
2.
BMC Med Genet ; 21(1): 203, 2020 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-33059634

RESUMO

BACKGROUND: HbH disease results from dysfunction of three, less commonly two, α-globin genes through various combinations of deletion and non-deletion mutations. Characterization of the mutations and the underlying genotypes is fundamental for proper screening and prevention of thalassaemia in any region. The aim of this study was to explore the genetic arrangements of HbH disease and to correlate the genotypes with the clinical phenotypes. METHODS: A total of 44 HbH disease patients were enrolled in this study. They were clinically and haematologically assessed. The patients were tested for 21 common α-globin gene mutations using multiplex PCR and reverse hybridization. According to the genotype, the patients were categorized into two separate sub-groups, deletion and non-deletion types HbH disease. RESULTS: Within the studied HbH disease patients, eight different α-globin gene mutations were detected in nine different genetic arrangements. The --MED and -α3.7 deletions were the two most frequently encountered mutations (37.5 and 35.2% respectively). Patients with deletion genotypes constituted 70.4%. The most common detected genotype was --MED/-α3.7 (59.1%), followed by αpoly-A1α/αpoly-A1α (13.6%). For the first time, coinheritance of two relatively mild mutations (-α3.7/ααAdana) was unpredictably detected in a 1.5 year-old child with Hb of 7.1 g/dL. CONCLUSION: The HbH disease patients' clinical characteristics were variable with no ample difference between the deletion and non-deletion types. These results can be of benefit for the screening and management of thalassaemia in this region.


Assuntos
Estudos de Associação Genética/métodos , Hemoglobina H/genética , Mutação , alfa-Globinas/genética , Talassemia alfa/genética , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Estudos de Associação Genética/estatística & dados numéricos , Genótipo , Humanos , Lactente , Iraque , Masculino , Pessoa de Meia-Idade , Fenótipo , Adulto Jovem , Talassemia alfa/diagnóstico
3.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 28(5): 1679-1682, 2020 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-33067973

RESUMO

OBJECTIVE: To investigate the values of mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), red cell osmotic fragility test(ROFT) and hemoglobin A2(HbA2) in screening of α-thalassemia in Guangdong area. METHODS: A total of 285 peripheral blood samples in patients treated in our hospital from January 2017 to December 2017 were collected. The detection of thalassemia gene was used as the gold standard, while blood routine examination, hemoglobin electrophoresis, and red cell osmotic fragility test were simultaneously performed. The optimal cut-off values in MCV, MCH, ROFT and HbA2 in α-thalassemia were determined by receiver operator characteristic curve (ROC curve). RESULTS: The most common types of α-thalassemia gene was --SEA/αα (54.59%). Compared with the control group, the differences in MCV, MCH, ROFT and HbA2 showed statistically significantce between different types of α-thalassemia (P<0.05). The best cut-off values of MCV, MCH, ROFT, and HbA2 in the diagnosis of α-thalassemia were 81.45 fl, 27.35 pg, 79.95%, and 2.55% respectively. CONCLUSION: For different laboratories, the cut-off values need to be established for screening α-thalassemia suitable in their own local region.The values of MCV, MCH, ROFT and HbA2 shows higher accuracy and sensitivity in the diagnosis of α-thalassemia. It is recommended to use MCV<81.45fl, MCH<27.35 pg, ROFT<79.95% and HbA2<2.55% as the standards for screening α-thalassemia in Guangdong area.


Assuntos
Índices de Eritrócitos , Talassemia alfa , Hemoglobina A2/análise , Humanos , Programas de Rastreamento , Sensibilidade e Especificidade , Talassemia alfa/diagnóstico , Talassemia alfa/genética
4.
MMWR Morb Mortal Wkly Rep ; 69(36): 1269-1272, 2020 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-32915167

RESUMO

Alpha-thalassemia comprises a group of inherited disorders in which alpha-hemoglobin chain production is reduced. Depending on the genotype, alpha-thalassemia results in moderate to profound anemia, hemolysis, growth delays, splenomegaly, and increased risk for thromboembolic events; certain patients might require chronic transfusions. Although alpha-thalassemia is not a core condition of the United States Recommended Uniform Screening Panel* for state newborn screening programs, methodologies used by some newborn screening programs to detect sickle cell disease, which is a core panel condition, also detect a quantitative marker of alpha-thalassemia, hemoglobin (Hb) Bart's, an abnormal type of hemoglobin. The percentage of Hb Bart's detected correlates with alpha-thalassemia severity. The Association of Public Health Laboratories' Hemoglobinopathy Workgroup conducted a survey of state newborn screening programs' alpha-thalassemia screening methodologies and reporting and follow-up practices. Survey findings indicated that 41 of 44 responding programs (93%) report some form of alpha-thalassemia results and 57% used a two-method screening protocol. However, the percentage of Hb Bart's used for thalassemia classification, the types of alpha-thalassemia reported, and the recipients of this information varied widely. These survey findings highlight the opportunity for newborn screening programs to revisit their policies as they reevaluate their practices in light of the recently released guideline from the Clinical and Laboratory Standards Institute (CLSI) on Newborn Screening for Hemoglobinopathies (1). Although deferring to local programs for policies, the report used a cutoff of 25% Hb Bart's in its decision tree, a value many programs do not use. Standardization of screening and reporting might lead to more timely diagnoses and health care services and improved outcomes for persons with a clinically significant alpha-thalassemia.


Assuntos
Triagem Neonatal/métodos , Talassemia alfa/diagnóstico , Feminino , Pesquisas sobre Serviços de Saúde , Humanos , Recém-Nascido , Masculino , Estados Unidos/epidemiologia , Talassemia alfa/epidemiologia
5.
BMC Med Genet ; 21(1): 170, 2020 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-32831051

RESUMO

BACKGROUND: The frequency of the alpha thalassemia trait is approximately 40% in the Kuwaiti population, but there has been no comprehensive study of the prevalent alleles. This is a report of patients who were referred for molecular diagnosis over a 20-year period. METHODS: This is a retrospective study of the α-globin genotypes obtained in the Hemoglobin Research Laboratory of the Department of Pediatrics, Kuwait University from 1994 to 2015. Genotyping was performed by a combination of PCR, allele-specific oligonucleotide hybridization and reverse dot blot hybridization (Vienna Lab Strip Assay). RESULTS: Four hundred samples were characterized and analyzed from individuals aged < 1 month to 80 years, with a median of 6 years from 283 unrelated families. Most (90.8%) were Kuwaiti nationals. The commonest genotype was homozygosity for the polyadenylation-1 mutation (αPA-1α/α PA-1α) in 33.3% of the samples, followed by heterozygosity (αα/α PA-1α) for the same mutation in 32.3%. PA-1 was therefore the most frequent allele (0.59). The frequency of the α0 (--MED) allele was 0.017. Rare alleles that were found in very low frequencies included α0 (--FIL) in a Filipino child, Hb Constant Spring, Hb Adana, and Hb Icaria. CONCLUSION: There is a wide variety of alpha thalassemia alleles among Kuwaitis, but nondeletional PA-1 is by far the most common cause of the moderate to severe HbH (ß4 tetramer) disease phenotype. The α0 (-MED) allele is also encountered, which has implications for premarital counseling, especially for the possibility of having babies with alpha thalassemia major (Barts hydrops fetalis).


Assuntos
alfa-Globinas/genética , Talassemia alfa/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Alelos , Criança , Pré-Escolar , Feminino , Frequência do Gene , Genótipo , Humanos , Lactente , Recém-Nascido , Kuweit , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem , Talassemia alfa/diagnóstico
6.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 37(3): 235-242, 2020 Mar 10.
Artigo em Chinês | MEDLINE | ID: mdl-32128738

RESUMO

Alpha-thalassemia is an autosomal recessive genetic disease as well as a relatively common hemoglobinopathy. Severe alpha-thalassemia (also known as Hb Bart's Hydrops fetalis syndrome) and intermediate alpha-thalassemia (also known as Hb H disease) are among the most common birth defects in southern China. To implement carrier screening and large population prevention program in high incidence areas can significantly reduce the incidence of alpha-thalassemia. This guideline was established by combining the discoveries of basic research, clinical research and guidelines from other countries and the actual data of Chinese population. It has summarized the medical genetics knowledge and key points in the clinical treatment for alpha-thalassemia, and provided suggestions for the clinical diagnosis and standard management of patients.


Assuntos
Hidropisia Fetal/diagnóstico , Hidropisia Fetal/terapia , Guias de Prática Clínica como Assunto , Talassemia alfa/diagnóstico , Talassemia alfa/terapia , China , Genética Médica , Hemoglobinas Anormais , Humanos
7.
J Assist Reprod Genet ; 37(3): 549-557, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32152910

RESUMO

PURPOSE: To evaluate the efficacy of preimplantation genetic testing (PGT) for α- and ß-double thalassemia combined with aneuploidy screening using next-generation sequencing (NGS). METHODS: An NGS-based PGT protocol was performed between 2017 and 2018 for twelve couples, each of which carried both α- and ß-thalassemia mutations. Trophectoderm biopsy samples underwent whole-genome amplification using multiple displacement amplification (MDA), followed by NGS for thalassemia detection and aneuploidy screening. A selection of several informative single nucleotide polymorphisms (SNPs) established haplotypes. Aneuploidy screening was performed only on unaffected noncarriers and carriers. Unaffected and euploid embryos were transferred into the uterus through frozen-thawed embryo transfer (FET). RESULTS: A total of 280 oocytes were retrieved following 18 ovum pick-up (OPU) cycles, with 182 normally fertilized and 112 cultured to become blastocysts. One hundred and seven (95.5%, 107/112) blastocysts received conclusive PGT results, showing 56 (52.3%, 56/107) were unaffected. Thirty-seven (66.1%, 37/56) of the unaffected were also identified as euploid. One family had no transferable embryos. Unaffected and euploid embryos were then transferred into the uterus of the other 11 couples resulting in 11 healthy live births. The clinical pregnancy rate was 61.1% (11/18) per OPU and 68.8% (11/16) per FET, with no miscarriage reported. Seven families accepted the prenatal diagnosis and received consistent results with the NGS-based PGT. CONCLUSION: This study indicated that NGS could realize the simultaneous PGT of double thalassemia and aneuploidy screening in a reliable and accurate manner. Moreover, it eliminated the need for multiple biopsies, alleviating the potential damages to the pre-implanted blastocysts.


Assuntos
Aneuploidia , Diagnóstico Pré-Implantação , Talassemia alfa/diagnóstico , Talassemia beta/diagnóstico , Aborto Espontâneo/genética , Aborto Espontâneo/patologia , Adulto , Blastocisto/metabolismo , Blastocisto/patologia , Transferência Embrionária/métodos , Feminino , Testes Genéticos/métodos , Humanos , Nascimento Vivo , Oócitos/crescimento & desenvolvimento , Gravidez , Taxa de Gravidez , Talassemia alfa/genética , Talassemia alfa/patologia , Talassemia beta/genética , Talassemia beta/patologia
8.
BMC Res Notes ; 13(1): 65, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-32041645

RESUMO

OBJECTIVE: Alpha-thalassemia is a genetic disorder characterized by deletions of one or more α globin genes that result in deficient of α globin chains reducing haemoglobin concentration. The study aimed to screen 97 patients with microcytosis and hypochromasia for the 3.7 and 4.2 alpha thalassemia deletion mutations. RESULTS: Out of 97 patients screened, only 7 were carriers for the 3.7 deletion and all patients were negative for the 4.2 deletion. The 3.7 deletion was found in Foor, Hawsa and Rezagat Sudanese tribes. In the carriers of the 3.7 deletion, Red Blood Cells and Haematocrit were significantly increased. The Red Blood Cells were 7.23 ± 0.78 × 1012/L in adult males and 7.21 ± 0.67 × 1012/L in adult females while in children were 5.07 ± 0.87 × 1012/L. The mean cell volume and mean cell haemoglobin were significantly decreased, but the mean cell haemoglobin concentration slightly decreased. Haemoglobin levels didn't revealed statistically significant decrease in adult males (11.7 ± 0.57 g/dL) and adult females (11.25 ± 0.64 g/dL), while in children were (11.6 ± 2.95 g/dL). Haemoglobin electrophoresis revealed two patients of the 3.7 and 4.2 negative were carriers for ß-thalassemia. The study concluded that α3.7 deletion has frequency of 0.07 in Sudanese with hypochromasia and microcytosis.


Assuntos
Anemia Hipocrômica/genética , Cromossomos Humanos Par 3/genética , Cromossomos Humanos Par 4/genética , Testes Genéticos , Talassemia alfa/diagnóstico , Talassemia alfa/genética , Adolescente , Adulto , Anemia Hipocrômica/epidemiologia , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Deleção de Sequência , Sudão/epidemiologia , Adulto Jovem , Talassemia alfa/epidemiologia
10.
Am J Obstet Gynecol ; 222(2): 185.e1-185.e17, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31394068

RESUMO

BACKGROUND: Thalassemia is one of the most common monogenetic diseases in the south of China and Southeast Asia. Hemoglobin Bart's hydrops fetalis syndrome was caused by a homozygous Southeast Asian deletion (-/-) in the HBA gene. Few studies have proved the potential of screen for Bart's hydrops fetalis using fetal cell-free DNA. However, the number of cases is still relatively small. Clinical trials of large samples would be needed. OBJECTIVE: In this study, we aimed to develop a noninvasive method of target-captured sequencing and genotyping by the Bayesian method using cell-free fetal DNA to identify the fetal genotype in pregnant women who are at risk of having hemoglobin Bart hydrops fetalis in a large-scale study. STUDY DESIGN: In total, 192,173 couples from 30 hospitals were enrolled in our study and 878 couples were recruited, among whom both the pregnant women and their husbands were detected to be carriers of Southeast Asian type (-/αα) of α-thalassemia. Prenatal diagnosis was performed by chorionic villus sampling, amniocentesis, or cordocentesis using gap-polymerase chain reaction considered as the golden standard. RESULTS: As a result, we found that the sensitivity and specificity of our noninvasive method were 98.81% and 94.72%, respectively, in the training set as well as 100% and 99.31%, respectively, in the testing set. Moreover, our method could identify all of 885 maternal samples with the Southeast Asian carrier and 36 trisomy samples with 100% of sensitivity in T13, T18, and T21 and 99.89% (1 of 917) and 99.88% (1 of 888) of specificity in T18 and T21, respectively. CONCLUSION: Our method opens the possibility of early screening for maternal genotyping of α-thalassemia, fetal aneuploidies in chromosomes 13/18/21, and hemoglobin Bart hydrops fetalis detection in 1 tube of maternal plasma.


Assuntos
Hemoglobinas Anormais/genética , Hidropisia Fetal/diagnóstico , Amniocentese , Teorema de Bayes , Ácidos Nucleicos Livres , Amostra da Vilosidade Coriônica , Cordocentese , Síndrome de Down/diagnóstico , Feminino , Genótipo , Heterozigoto , Humanos , Hidropisia Fetal/genética , Teste Pré-Natal não Invasivo , Gravidez , Sensibilidade e Especificidade , Síndrome da Trissomia do Cromossomo 13/diagnóstico , Síndrome da Trissomía do Cromossomo 18/diagnóstico , Talassemia alfa/diagnóstico , Talassemia alfa/genética
11.
J Clin Pathol ; 73(5): 278-282, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31653757

RESUMO

AIMS: Thalassemia is one of the most prevalent inherited disorders in south China. However, there still has no comprehensive research on molecular characterisation of α-thalassemia and ß-thalassemia in the Quanzhou region of Fujian province, a city with high incidence of thalassemia in Southeast China. METHODS: A total of 11 668 cases were collected in Quanzhou region from January 2013 to June 2019. The deletions of α-thalassemia were detected by Gap-PCR, α-thalassemia and ß-thalassemia mutations were detected by DNA reverse dot blot hybridisation. Rare thalassemia gene testing and DNA sequencing were performed to detect rare and novel thalassemia mutation for suspected rare thalassemia carriers. RESULTS: Among 11 668 subjects, 4796 (41.10%) subjects were diagnosed with thalassemia. 3298 (28.27%) subjects were α-thalassemia carriers, 26 types of α-thalassemia mutations were identified, with the common α-thalassemia genotypes being --SEA/αα (71.47%), -α3.7/αα (17.13%) and -α4.2/αα (3.49%). 1407 (12.06%) subjects were ß-thalassemia carriers, 18 types of ß-thalassemia mutations were identified. The common five genotypes of ß-thalassemia were ßIVS-II-654/ßN (36.53%), ßCD41-42/ßN (30.28%), ßCD17/ßN (17.13%), ßCD26/ßN (5.12%) and ß-28/ßN (4.62%). Additionally, 91 (0.78%) subjects with composite α-thalassemia and ß-thalassemia were identified. Furthermore, 9 α-thalassemia and ß-thalassemia gene mutations (CAP +40-43 (-AAAC), IVS-I-1 (G>T), IVS-I-5 (G>C), SEA-HPFH, CD53 (-T), CD37 (A>G), -90 (C>T), CD3 (T>C), -α6.9) were identified for the first time in the region. Among them, CD53 (-T), CD37 (A>G) and -90 (C>T) mutations were identified for the first time in Fujian province. Moreover, CD3 (T>C), -α6.9 mutations were first identified in Chinese individual. CONCLUSIONS: Quanzhou region of South China has high incidence of thalassemia mutations. In this study, several cases of rare thalassemia mutations have been identified, providing reference for clinical consultation. The completion of this study is of great significance to strengthen the prevention and control of thalassaemia in the Quanzhou region.


Assuntos
Mutação , Talassemia alfa/genética , Talassemia beta/genética , Adolescente , Adulto , China , Feminino , Marcadores Genéticos , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Análise de Sequência de DNA , Adulto Jovem , Talassemia alfa/diagnóstico , Talassemia alfa/epidemiologia , Talassemia beta/diagnóstico , Talassemia beta/epidemiologia
12.
J Clin Pathol ; 73(1): 14-16, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31434698

RESUMO

AIMS: Untranslated regions (UTRs) play an important role in post-transcriptional regulation of gene expression, including by modulating messenger RNA (mRNA) transport out of the nucleus, translation efficiency, subcellular localisation and stability. Any mutation in this region could alter the stability of mRNA and thereby affect protein synthesis. We analysed if a mutation located in the α complex protected region of the α1 globin gene could cause non-deletional α-thalassaemia by affecting post-transcriptional stability (mRNA stability). METHODS: A total of 14 patients without anaemia, normal or slight microcytosis and hypochromia (medium concentration haemoglobin [MCH] <27 pg) were studied. Haemoglobin subtypes were screened using capillary zone electrophoresis and ion-exchange high-performance liquid chromatography (VARIANT II ß-Thalassaemia Short Program). The most common α-globin mutations were identified by multiplex PCR (Alpha-Globin StripAssay kit) and the molecular characterisation by automatic sequencing of alpha globin genes. RESULTS: All of them shown a novel transversion mutation in nt 778 (C>A), which is located in the 3' UTR in the α complex protected region [HBA1: c.*+46C>A]. CONCLUSIONS: This mutation is in the αRNAmin binding site, so a single nucleotide substitution in this region can decrease mRNA stability by potentially compromising the binding of α-complex protein to αRNAmin, favouring the decay of α-globin mRNA via erythroid cell-enriched endoribonuclease cleavage. In this case, it is a non-deletional α-thalassaemia. However, in silico and empirical studies predicted that it could be a silent polymorphism. Functional studies should be carried out to confirm whether it is a pathological mutation or a silent polymorphism.


Assuntos
Regiões 3' não Traduzidas , Mutação , Polimorfismo Genético , Estabilidade de RNA , RNA Mensageiro/genética , alfa-Globinas/genética , Talassemia alfa/genética , Adolescente , Adulto , Estudos de Casos e Controles , Criança , Pré-Escolar , Análise Mutacional de DNA/métodos , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase Multiplex , Fenótipo , RNA Mensageiro/metabolismo , Fatores de Risco , alfa-Globinas/metabolismo , Talassemia alfa/sangue , Talassemia alfa/diagnóstico
13.
Hemoglobin ; 43(4-5): 245-248, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31687860

RESUMO

The capillary electrophoresis (CE) system allows the quantification of Hb Bart's (γ4) and Hb H (ß4) that is used for screening of Hb H disease. However, Hb Bart's hydrops fetalis and Hb H are not always codetected in patients with Hb H disease. In this study, 35 samples were analyzed for the α0-thalassemia (α0-thal) [- -SEA (Southeast Asian) and - -THAI (Thailand)] deletions and the α+-thal [-α3.7 (rightward) and -α4.2 (leftward)] type deletions using real time-polymerase chain reaction (real time-PCR) with SYBR Green1 and high-resolution melting (HRM) analysis and conventional gap-PCR techniques, respectively. Results showed that 28 of 29 (96.6%) samples with the Hb A2-Hb H phenotype on CE electrophoregrams presented the genotype of - -SEA/-α3.7, while the - -SEA/-α4.2 made up the remainder. The - -SEA/-α3.7 genotype was also found in all six samples (100.0%) with Hb A2-Hb Bart's on CE electrophoregrams. Thus, for genetic counseling, prevention and control programs of Hb Bart's hydrops fetalis and Hb H disease, α-thal genotype analysis is required.


Assuntos
Eletroforese Capilar/métodos , Hemoglobina A2/genética , Hemoglobina H/genética , Hemoglobinas Anormais/genética , Deleção de Sequência , Feminino , Genótipo , Humanos , Hidropisia Fetal/diagnóstico , Gravidez , Diagnóstico Pré-Natal/métodos , Talassemia alfa/diagnóstico , Talassemia alfa/genética
14.
PLoS One ; 14(10): e0223996, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31661492

RESUMO

α0-Thalassemia is an inherited hematological disorder caused by the deletion of α-globin genes. The Southeast Asian deletion (--SEA) is the most common type of α0-thalassemia observed in Southeast Asian countries. Regarding WHO health policy, an effective α0-thalassemia screening strategy is needed to control new severe α-thalassemia cases. In this study, a monoclonal antibody panel was used to develop immunochromatographic (IC) strip tests for detecting the Hb Bart's and ζ-globin chain. Among 195 samples, all α0-thalassemia traits (78 α0-thalassemia (--SEA) and 4 α0-thalassemia (--THAI)) had low MCV or MCH values. The sensitivity, specificity, PPV and NPV of the IC strip tests for ζ-globin and Hb Bart's for screening α0-thalassemia (--SEA) within the low MCV or MCH samples were 100%, 65.2%, 90.7%, 100% and 96.2%, 47.8%, 86.6%, 78.6%, respectively. All 4 α0-thalassemia (--THAI) traits were negative for ζ-globin chains but positive for Hb Bart's using the IC strip tests. These results led to a α0-thalassemia screening being proposed in which blood samples are first evaluated by MCV, MCH and Hb typing. Samples with high MCV and MCH values are excluded for the presence of the α0-thalassemia gene. Samples with low MCV or MCH values are assayed using the developed IC strip tests, where only samples testing positive are further assayed for α0-thalassemia by PCR. Patients with Hb H, EA Bart's or EF Bart's diseases do not need to use this IC strip assay. Thus, in this study, a simple and cost effective α0-thalassemia point of care test was developed.


Assuntos
Cromatografia de Afinidade/métodos , Hemoglobinas Anormais/análise , Talassemia alfa/classificação , Talassemia alfa/diagnóstico , Globinas zeta/análise , Estudos de Casos e Controles , Diagnóstico Diferencial , Humanos , Talassemia alfa/sangue
15.
Int J Lab Hematol ; 41(5): 650-656, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31271507

RESUMO

INTRODUCTION: Thalassemias and hemoglobinopathies are the most prevalent inherited anemias detected in South East Asians. These disorders represent not only a clinical health problem but also a socioeconomic problem for this region. Regarding the prevention and control of thalassemias and hemoglobinopathies in the Lao PDR, screening and diagnostic strategies should be strongly considered. The knowledge about the prevalence and molecular genotyping of thalassemias and hemoglobinopathies among the Lao Loum group, which includes the majority of Lao people, is now limited, making the prevention and control of thalassemias difficult. METHODS: This study aimed to determine the prevalence of thalassemia among Lao Loum subjects of reproductive age. Multiplex gap PCR and direct sequencing were used to investigate the mutations of α-globin and ß-globin genes. RESULTS: Thalassemias and hemoglobinopathies were detected in 154 of 354 (43.50%) patients, and 22 different genotypes were identified in this cohort. Remarkably, high frequencies of hemoglobin E, α0 -thalassemia (--SEA ), and α+ -thalassemia (-α3.7 ) were noted. A variety of hematologic features was observed, including co-inheritance of heterozygous HbE and heterozygous α-thalassemia, which was associated with significantly lower levels of MCV and MCH values than those observed in typical HbE heterozygotes. Female participants who were heterozygous for ß0 or co-inheritance of heterozygous ßE with heterozygous α-thalassemia exhibited mild anemia. CONCLUSION: Our data show that thalassemias and hemoglobinopathies have become health problems imposing a serious burden in the Lao PDR. Prevention programs aimed at decreasing the incidence of severe thalassemia diseases should be designed and initiated.


Assuntos
Hemoglobina E/genética , Hemoglobinopatias/genética , Mutação , alfa-Globinas/genética , Talassemia alfa/genética , Talassemia beta/genética , Adolescente , Feminino , Frequência do Gene , Testes Genéticos/métodos , Genótipo , Hemoglobinopatias/diagnóstico , Hemoglobinopatias/epidemiologia , Humanos , Laos/epidemiologia , Masculino , Prevalência , Adulto Jovem , Talassemia alfa/diagnóstico , Talassemia alfa/epidemiologia , Talassemia beta/diagnóstico , Talassemia beta/epidemiologia
16.
Hemoglobin ; 43(1): 52-55, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31106603

RESUMO

This study reports the case of 2-year-old Northeastern Thai girl with ß-thalassemia (ß-thal) disease who has required regular blood transfusions since she was 8 months old. Hemoglobin (Hb) analysis by high performance liquid chromatography (HPLC) separated Hb A2/E (16.5%), Hb F (22.7%), Hb A (51.8%) and an abnormal peak (Hb X) found at a retention time (RT) of 5.05 min. (C-window) with 2.8%. Multiplex gap-polymerase chain reaction (gap-PCR) revealed heterozygous α-thalassemia-2 (α-thal-2) (-α3.7/αα; NG_000006.1: g.34164_37967 del3804). This patient was suspected of having a ß-globin chain variant and Hb E (HBB: c.79G>A) according to the high Hb F level and disease presentations. Surprisingly, Hb Mahasarakham (the geographic origin of the proband), a novel single nucleotide deletion (-G) at the first nucleotide of codon 121 (HBB: c.364delG), was identified by direct DNA sequencing and secondary confirmation by PCR-restriction fragment length polymorphism (PCR-RFLP). This novel mutation causes a frameshift mutation and added 10 more residues to the ß-globin chain that was elongated to 156 amino acids. Molecular basis of this novel mutation in the heterozygous state is required to confirm the mode of inheritance.


Assuntos
Heterozigoto , Mutação , Domínios Proteicos/genética , Talassemia alfa/diagnóstico , Talassemia alfa/genética , Globinas beta/genética , Alelos , Substituição de Aminoácidos , Sequência de Bases , Pré-Escolar , Análise Mutacional de DNA , Eritrócitos/patologia , Feminino , Hemoglobinas Anormais/genética , Humanos , Globinas beta/química
17.
Pediatr Blood Cancer ; 66(8): e27807, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31094093

RESUMO

BACKGROUND: The Uganda Sickle Surveillance Study provided evidence for a large sickle burden among HIV-exposed infants in Uganda. To date, however, no large scale screening program has been developed for Central or East Africa. METHODS: A 3-year targeted sickle cell screening project in Uganda was designed by the Ministry of Health to (1) determine sickle cell trait and disease prevalence within high-burden districts, (2) document the prevalence among HIV-exposed and nonexposed children, (3) confirm previously suggested HIV comorbidity, and (4) estimate the co-inheritance of known genetic modifiers of sickle cell disease. RESULTS: A total of 163 334 dried blood spot samples collected between April 2015 and March 2018 were analyzed, including 112 352 samples within the HIV Early Infant Diagnosis program. A high burden with >1% sickle cell disease was found within targeted East Central and Mid-Northern districts, in both HIV-exposed and nonexposed children. Based on crude birth-rate data, 236 905 sickle cell trait births and 16 695 sickle cell disease births will occur annually in Uganda. Compared to sickle cell disease without HIV, the odds ratio of having sickle cell disease plus HIV was 0.50 (95% confidence interval = 0.40-0.64, P < .0001). Alpha-thalassemia trait and G6PD deficiency were common with sickle cell disease, but with different geospatial distribution. CONCLUSIONS: High sickle cell burden and potential HIV comorbidity are confirmed in Uganda. Genetic modifiers are common and likely influence laboratory and clinical phenotypes. These prospective data document that targeted sickle cell screening is feasible and effective in Uganda, and support development of district-level comprehensive care programs.


Assuntos
Anemia Falciforme/diagnóstico , Genes Modificadores , Deficiência de Glucosefosfato Desidrogenase/diagnóstico , Infecções por HIV/diagnóstico , Programas de Rastreamento/métodos , Talassemia alfa/diagnóstico , Anemia Falciforme/complicações , Anemia Falciforme/epidemiologia , Anemia Falciforme/genética , Pré-Escolar , Comorbidade , Feminino , Seguimentos , Deficiência de Glucosefosfato Desidrogenase/complicações , Deficiência de Glucosefosfato Desidrogenase/epidemiologia , Deficiência de Glucosefosfato Desidrogenase/genética , HIV/genética , HIV/isolamento & purificação , Infecções por HIV/complicações , Infecções por HIV/epidemiologia , Infecções por HIV/genética , Humanos , Lactente , Recém-Nascido , Masculino , Prevalência , Prognóstico , Estudos Prospectivos , Talassemia alfa/complicações , Talassemia alfa/epidemiologia , Talassemia alfa/genética
18.
Hemoglobin ; 43(1): 73-75, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31104519

RESUMO

A regulatory single nucleotide polymorphism (rSNP), the Aγ (+25 G>A) (rs368698783) (NG_000007.3: g47783G>A) located in the HBG1 proximal promoter, is a significant predictor of clinical severity by elevating Hb F levels in ß-thalassemia (ß-thal). In this study, the presence of the Aγ (+25 G>A) and Aγ (+25 A>A) genotypes was investigated in four subgroups from a total of 611 subjects, including 88 α-thalassemia (α-thal) carriers (group A), 162 ß-thal carriers of point mutations (group B), 57 carriers of ß-thal deletions (group C) and 152 non thalassemic individuals (group D). The result is that the genotypes G>A and A>A exhibit significantly high levels of Hb F compared with the genotype G>G in both groups B and C, while no significant difference was observed in both groups A and D. We assume that the effect of Aγ (+25 G>A) polymorphism on Hb F production is only under erythropoietic stress characteristic for ß-globin chain deficiency.


Assuntos
Alelos , Eritropoese/genética , Hemoglobina Fetal/genética , Genes Modificadores , Polimorfismo de Nucleotídeo Único , Globinas beta/genética , Talassemia beta/diagnóstico , Talassemia beta/genética , Índices de Eritrócitos , Feminino , Genótipo , Humanos , Fatores de Transcrição Kruppel-Like/genética , Masculino , Análise de Sequência de DNA , Talassemia alfa/diagnóstico , Talassemia alfa/genética
19.
Hemoglobin ; 43(1): 4-6, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31084368

RESUMO

Interest in α-globin point mutations has increased in the past few years because nondeletional variations can affect protein function and stability, giving rise to hemoglobin (Hb) variants that present a wide spectrum of phenotypes, from asymptomatic forms to hemolytic anemia. We describe a novel α1-globin gene variant, which we have named Hb Milano [α109(G16)Leu→Pro (CTG>CCG); HBA1: c.329T>C]. We performed high performance liquid chromatography (HPLC) to carry out Hb analysis, capillary electrophoresis (CE) for Hb separation and quantitation of Hb subtypes, two tests on stroma-free lysates for evaluating Hb stability, multiplex ligation-dependent probe amplification (MLPA) to detect deletions/duplications within the α gene cluster and Sanger sequencing of the α-globin genes. No abnormal Hb variants were identified by HPLC and CE. Isopropanol and stability tests were negative. The peripheral blood film showed no inclusions such as Hb H or Heinz bodies. Multiplication ligation-dependent probe amplification of the α-globin gene cluster detected a heterozygosity for the -α3.7 (rightward) deletion. Direct sequencing of the α-globin genes identified the Hb Milano variant on the HBA1 gene. No mutations were found on the HBA2 gene. The clinical consequences of the Hb Milano variant differ based on the genotype: according to our study, the hematological parameters range from a marked microcythemia with mild anemia if the variant is coinherited with an α gene deletion, to mild microcytosis when the variant is not associated with α gene deletions.


Assuntos
Substituição de Aminoácidos , Grupo com Ancestrais do Continente Europeu/genética , Genótipo , Hemoglobina A Glicada/genética , Hemoglobinas Anormais/genética , Mutação , alfa-Globinas/genética , Adulto , Sequência de Bases , Cromatografia Líquida de Alta Pressão , Feminino , Humanos , Itália , Fenótipo , Talassemia alfa/diagnóstico , Talassemia alfa/genética
20.
Hemoglobin ; 43(1): 66-68, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30843739

RESUMO

We describe a proband originating from Al-Quneitra Province, Syria. His hematology data was as follows: Hb A 24.7%, Hb F 71.1%, Hb A2 4.2%. Molecular analysis, based on DNA sequencing of the ß-globin gene mutation, showed for the first time a compound heterozygous IVS-I-1 (G>A) (HBB: c.92+1G>A)/IVS-II-705 (T>G) (HBB: c.316-146T>G) on the ß-globin gene. A reverse hybridization technique revealed that the proband was also an α-thalassemia (α-thal) -α3.7 (rightward) deletion carrier. Haplotypes analysis for the seven polymorphic restriction sites showed that the compound heterozygous mutations, IVS-I-1/IVS-II-705, were linked to two haplotypes: I [+ - - - - + +] and VI [- + + - - - +], respectively. Our results showed, for the first time, the presence of rare ß-thalassemia (ß-thal) IVS-II-705 (T>G) mutation associated with IVS-I-1 (G>A). Our findings suggest the presence of these mutations resulted from past migrations.


Assuntos
Alelos , Íntrons , Mutação , alfa-Globinas/genética , Talassemia alfa/diagnóstico , Talassemia alfa/genética , Globinas beta/genética , Talassemia beta/diagnóstico , Talassemia beta/genética , Adolescente , Análise Mutacional de DNA , Índices de Eritrócitos , Família , Haplótipos , Heterozigoto , Humanos , Masculino , Linhagem , Síria , Talassemia alfa/sangue , Talassemia beta/sangue
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA