Identification of deletion and triple α-globin gene haplotypes in the montreal β-thalassemia screening program: Implications for genetic medicine

1990 ◽  
Vol 36 (1) ◽  
pp. 76-84 ◽  
Author(s):  
Beverly R. Akerman ◽  
T. Mary Fujiwara ◽  
Gerald A. Lancaster ◽  
Kenneth Morgan ◽  
Charles R. Scriver
Keyword(s):  
Screening Program ◽  
Globin Gene ◽  
Genetic Medicine ◽  
Thalassemia Screening

scholarly journals Splice-site and Frameshift Mutations of β-Globin Gene Found in Thalassemia Carrier Screening in Yogyakarta Special Region, Indonesia

2021 ◽  
Vol 13 (1) ◽  
pp. 55-60
Author(s):  
Niken Satuti Nur Handayani ◽  
Nailil Husna ◽  
Gunawan Rahmil ◽  
Riris Anindya Ghifari ◽  
Lily Widyawati ◽  
...  
Keyword(s):  
Splice Site ◽  
Prevention Program ◽  
Screening Program ◽  
Globin Gene ◽  
Carrier Screening ◽  
Amplification Refractory Mutation System ◽  
Frameshift Mutations ◽  
Blood Disorder ◽  
Thalassemia Screening ◽  
Special Region

BACKGROUND: β-thalassemia is an inherited blood disorder that relatively common in Southeast Asian countries. In Indonesia, it is estimated that 200,000 infants with thalassemia carrier born each year. Mutation causing β-thalassemia is highly varied and relatively specific in a population. This study aimed to identify the mutations responsible for β-thalassemia from Thalassemia Carrier Screening conducted in Yogyakarta Special Region. This information is beneficial for developing a strategic prevention program to control thalassemia in the region.METHODS: Twenty-eight blood samples of haematologically suspected β-thalassemia from participant of thalassemia screening program in Yogyakarta Special Region were investigated for β-globin gene mutation by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), amplification refractory mutation system (ARMS) and DNA sequencing.RESULTS: Our samples showed average HbA2 value of 5±0.81% and HbF value of 2±2.29%. It showed eight abnormal erythrocyte morphologies dominated by hypochromia (96.4%), cigar cell (85.7%), and microcytosis (78.6%). Our molecular investigation identified three splice-site mutations namely InterVening Sequence (IVS)-1-5 (G>C) (71.4%), IVS-1-2 (T>C) (7.1%), and IVS-1-1 (G>T) (3.6%), two frameshift mutations that are CD35 (-C) (10.7%) and CD8/9 (+G) (3.6%), and a missense mutation of CD6 (GAG>GTG) (3.6%).CONCLUSION: Our study concluded on a high prevalence of IVS-1-5 (G>C) mutation in Yogyakarta Special Region. This mutation information is significant for developing a strategic prevention program to control thalassemia in the region, for example for developing a rapid molecular test for future screening program.KEYWORDS: β-Globin gene, thalassemia, screening, carrier, mutation, Yogyakarta

scholarly journals In silico prediction of HBD gene variants in the Iranian population

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Keivan Moradi ◽  
Aboozar Mohammadi ◽  
Mohsen Kazeminia
Keyword(s):  
Persian Gulf ◽  
Globin Gene ◽  
Iranian Population ◽  
Gene Variants ◽  
In Silico Prediction ◽  
Screening Programs ◽  
Prediction Tools ◽  
Clinical Laboratories ◽  
The Persian Gulf ◽  
Thalassemia Screening

Abstract Background The quantification of hemoglobin A2 (Hb A2; α2δ2) is used as a valuable test to differentiate α- and ß-thal carriers in clinical laboratories. Therefore, the HBD (δ-globin) gene variants could result in reduced levels of Hb A2 and have implications for thalassemia screening programs. The aim of the present study was to predict the consequences of HBD gene variants identified in the Iranome project. Results The highest number of variants was in the Persian Gulf Islanders. The variants of p.Gln132Glu (HBD: c.394C>G), p.Gly17Arg (HBD: c.49G>C), p.Thr5Ile (HBD: c.14C>T), and p.Ala28Ser (HBD: c.82G>T) presented damage results in three or more prediction tools. In addition, it seems that the p.Gly30= (HBD: c.90C>T) decreases the use of authentic splice and, instead, creates a new donor splice site (DSS) or leads to the use of a cryptic DSS. Conclusions Most of these variants have been associated with a decrease in Hb A2 levels. Due to the high mutational diversity in the HBB gene in the Iranian population and the use of Hb A2 quantification to differentiate α- and ß-thal carriers among Iranian clinical laboratories, some attention should be taken to a possible co-inheritance of HBD gene variants to avoid the misdiagnosis of ß-thal carriers.

scholarly journals Evaluation of Technical Issues in a Pilot Multicenter Newborn Screening Program for Sickle Cell Disease

2018 ◽  
Vol 5 (1) ◽  
pp. 2
Author(s):  
Maddalena Martella ◽  
Giampietro Viola ◽  
Silvia Azzena ◽  
Sara Schiavon ◽  
Andrea Biondi ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Newborn Screening ◽  
Molecular Analysis ◽  
Sickle Cell ◽  
Screening Program ◽  
Globin Gene ◽  
False Negative ◽  
Confirmatory Test ◽  
Cell Disease ◽  
Technical Issues

A multicenter pilot program for universal newborn screening of Sickle cell disease (SCD) was conducted in two centres of Northern Italy (Padova and Monza). High Performance Liquid Chromatography (HPLC) was performed as the first test on samples collected on Guthrie cards and molecular analysis of the β-globin gene (HBB) was the confirmatory test performed on the HPLC-positive or indeterminate samples. 5466 samples of newborns were evaluated. Of these, 5439/5466 were submitted to HPLC analysis and the molecular analysis always confirmed in all the alteration detected in HPLC (62/5439 newborns); 4/5439 (0.07%) were SCD affected, 37/5439 (0.68%) were HbAS carriers and 21/5439 (0.40%) showed other hemoglobinopathies. Stored dried blood spots were adequate for HPLC and β-globin gene molecular analysis. Samples were suitable for analysis until sixteen months old. A cut-off of A1 percentage, in order to avoid false negative or unnecessary confirmation tests, was identified. Our experience showed that several technical issues need to be addressed and resolved while developing a multicenter NBS program for SCD in a country where there is no national neonatal screening (NBS) program for SCD and NBS programs occur on a regional basis.

Genetic epidemiology of beta-thalassemia in the Maldives: 23 years of a beta-thalassemia screening program

Gene ◽  
2020 ◽  
Vol 741 ◽  
pp. 144544
Author(s):  
Ibrahim Mustafa ◽  
Naila Firdous ◽  
Fatma M. Shebl ◽  
Zumin Shi ◽  
Mariya Saeed ◽  
...  
Keyword(s):  
Genetic Epidemiology ◽  
Screening Program ◽  
Beta Thalassemia ◽  
Thalassemia Screening

EE score: an index for simple differentiation of homozygous hemoglobin E and hemoglobin E-β0-thalassemia

2018 ◽  
Vol 56 (9) ◽  
pp. 1507-1513 ◽  
Author(s):  
Kritsada Singha ◽  
Goonnapa Fucharoen ◽  
Kanokwan Sanchaisuriya ◽  
Supan Fucharoen
Keyword(s):  
Predictive Value ◽  
Dna Analysis ◽  
Screening Program ◽  
Inverse Correlation ◽  
Molecular Testing ◽  
Related Disorder ◽  
Hemoglobin E ◽  
Dna Analyses ◽  
Homozygous Hemoglobin E ◽  
Thalassemia Screening

Abstract Background: The objective of the study was to describe a formula based on hemoglobin (Hb)A2 and HbF levels for differentiation of homozygous HbE and HbE-β-thalassemia. Methods: A total of 1256 subjects suspected for homozygous HbE or HbE-β0-thalassemia were recruited at the ongoing thalassemia screening program at Khon Kaen University, Thailand. Hb analysis was done using capillary electrophoresis. Genotyping was based on DNA analysis. An arbitrary formula based on HbA2 and HbF was developed statistically for differentiation of the two conditions. Validation was carried out prospectively on another 139 subjects encountered at routine laboratory. Results: Among 1256 subjects, Hb and DNA analyses identified cases with homozygous HbE (n=1076, 85.7%), HbE-β0-thalassemia (n=140, 11.1%), HbE-δβ0-thalassemia (n=30, 2.4%) and unknown HbE-related disorder (n=10, 0.8%). An inverse correlation between the amounts of HbA2 and HbF in HbE-β0-thalassemia was observed. With differences in the amounts of HbA2 and HbF between the groups, an arbitrary score (7.3 HbA2+HbF) was developed where score above 60 indicated HbE-β0-thalassemia. Application of this score on another 139 subjects showed accurate prediction of HbE-β0-thalassemia with 100% sensitivity, 96.5% specificity, 85.7% positive predictive value and 100% negative predictive value. Successful application onto couples at risk was demonstrated. Conclusions: An established score should prove useful in the differentiation of homozygous HbE and HbE-β0-thalassemia in routine setting and lead to a significant reduction in number of referring cases for molecular testing.

scholarly journals Enhancing Genetic Medicine: Rapid and Cost-Effective Molecular Diagnosis for a GJB2 Founder Mutation for Hearing Impairment in Ghana

Genes ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 132 ◽  
Author(s):  
Samuel M. Adadey ◽  
Edmond Tingang Wonkam ◽  
Elvis Twumasi Aboagye ◽  
Darius Quansah ◽  
Adwoa Asante-Poku ◽  
...  
Keyword(s):  
Hearing Impairment ◽  
Restriction Enzyme ◽  
Sanger Sequencing ◽  
Screening Program ◽  
Cost Effective ◽  
Normal Hearing ◽  
Hearing Impaired ◽  
Practical Case ◽  
Junction Protein ◽  
Genetic Medicine

In Ghana, gap-junction protein β 2 (GJB2) variants account for about 25.9% of familial hearing impairment (HI) cases. The GJB2-p.Arg143Trp (NM_004004.6:c.427C>T/OMIM: 121011.0009/rs80338948) variant remains the most frequent variant associated with congenital HI in Ghana, but has not yet been investigated in clinical practice. We therefore sought to design a rapid and cost-effective test to detect this variant. We sampled 20 hearing-impaired and 10 normal hearing family members from 8 families segregating autosomal recessive non syndromic HI. In addition, a total of 111 unrelated isolated individuals with HI were selected, as well as 50 normal hearing control participants. A restriction fragment length polymorphism (RFLP) test was designed, using the restriction enzyme NciI optimized and validated with Sanger sequencing, for rapid genotyping of the common GJB2-p.Arg143Trp variant. All hearing-impaired participants from 7/8 families were homozygous positive for the GJB2-p.Arg143Trp mutation using the NciI-RFLP test, which was confirmed with Sanger sequencing. The investigation of 111 individuals with isolated non-syndromic HI that were previously Sanger sequenced found that the sensitivity of the GJB2-p.Arg143Trp NciI-RFLP testing was 100%. All the 50 control subjects with normal hearing were found to be negative for the variant. Although the test is extremely valuable, it is not 100% specific because it cannot differentiate between other mutations at the recognition site of the restriction enzyme. The GJB2-p.Arg143Trp NciI-RFLP-based diagnostic test had a high sensitivity for genotyping the most common GJB2 pathogenic and founder variant (p.Arg143Trp) within the Ghanaian populations. We recommend the adoption and implementation of this test for hearing impairment genetic clinical investigations to complement the newborn hearing screening program in Ghana. The present study is a practical case scenario of enhancing genetic medicine in Africa.

scholarly journals Molecular Epidemiology and Hematologic Characterizationof δβ-thalassemia and Hereditary Persistence of Fetal Hemoglobin in 125661 Families of Greater Guangzhou Area, the metropolis of Southern China

2020 ◽  
Author(s):  
FAN JIANG ◽  
Can Liao
Keyword(s):  
Genetic Counseling ◽  
Molecular Epidemiology ◽  
Gene Cluster ◽  
Southern China ◽  
Globin Gene ◽  
Fetal Hemoglobin ◽  
Screening Programs ◽  
Globin Gene Cluster ◽  
Prenatal Diagnostic ◽  
Thalassemia Screening

Abstract Background: Individuals with δβ-thalassemia/HPFH and β-thalassemia usually present with intermedia or thalassemia major. No large-scale survey on HPFH/δβ-thalassemia in southern China has been reported to date. The purpose of this study was to examine the molecular epidemiology and hematologic characteristics of these disorders in Guangzhou, the largest city in Southern China, to offer advice for thalassemia screening programs and genetic counseling. Methods: A total of 125,661 couples participated in pregestational thalassemia screening. 654 subjects with fetal hemoglobin (HbF) level≥5% were selected for further investigation. Gap-PCR combined with Multiplex ligation dependent probe amplification (MLPA) were used to screen for β-globin gene cluster deletions. Gene sequencing for the promoter region of HBG1 /HBG2 gene were performed for all those subjects. Results: A total of 654 individuals had hemoglobin (HbF) levels≥5%, and 0.12% of the couples were found to be heterozygous for HPFH/δβ-thalassemia, including Chinese Gγ(Aγδβ)0-thal, Southeast Asia HPFH (SEA-HPFH), Taiwanese deletion and Hb Lepore–Boston–Washington. The highest prevalence was observed in the Huadu district and the lowest in the Nansha district. Three cases were identified as carrying β-globin gene cluster deletions, which had not been previously reported. Two at-risk couples (0.0015%) were required to receive prenatal diagnosis. We also found 55 cases of nondeletional-HPFH (nd-HPFH), including 54 with Italian nd-HPFH and one with the A γ-197C-T heterozygous state. It is difficult to discriminate between Chinese G γ( A γδβ) 0 -thal and Italian nd-HPFH carriers using hemoglobin (Hb) analysis. Conclusions: This study is the first to describe the familial prevalence of HPFH/δβ-thalassemia and the high-risk rate in in Greater Guangzhou Area, and the findings will support the implementation of thalassemia screening for three common deletions by gap-PCR. We also presented a systematic description of genotype-phenotype relationships which will be useful for genetic counseling and prenatal diagnostic services for β-thalassemia intermedia. Keywords: Prevalence, δβ-thalassemia, HPFH, Guangzhou

scholarly journals Molecular Epidemiology and Hematologic Characterizationof δβ-thalassemia and Hereditary Persistence of Fetal Hemoglobin in 125661 Families of Greater Guangzhou Area, the metropolis of Southern China

2019 ◽  
Author(s):  
FAN JIANG ◽  
Can Liao
Keyword(s):  
Genetic Counseling ◽  
Molecular Epidemiology ◽  
Gene Cluster ◽  
Southern China ◽  
Globin Gene ◽  
Fetal Hemoglobin ◽  
Screening Programs ◽  
Globin Gene Cluster ◽  
Prenatal Diagnostic ◽  
Thalassemia Screening

Abstract Background:Individuals with δβ-thalassemia/HPFH and β-thalassemia usually present with intermedia or thalassemia major. No large-scale survey on HPFH/δβ-thalassemia in southern China has been reported to date. The purpose of this study was to examine the molecular epidemiology and hematologic characteristics of these disorders in Guangzhou, the largest city in Southern China, to offer advice for thalassemia screening programs and genetic counseling. Methods: A total of 125,661 couples participated in pregestational thalassemia screening. 654 subjects with fetal hemoglobin (Hb F) level ≥5% were selected for further investigation. Gap-PCR combined with Multiplex ligation dependent probe amplification (MLPA) were used to screen for β-globin gene cluster deletions. Gene sequencing for the promoter region of HBG1 /HBG2 gene were performed for all those subjects. Results: A total of 654 individuals had hemoglobin (HbF) levels ≥5%, and 0.12% of the couples were found to be heterozygous for HPFH/δβ-thalassemia, including Chinese Gγ(Aγδβ)0-thal, Southeast Asia HPFH (SEA-HPFH), Taiwanese deletion and Hb Lepore–Boston–Washington. The highest prevalence was observed in the Huadu district and the lowest in the Nansha district. Three cases were identified as carrying β-globin gene cluster deletions, which had not been previously reported. Two at-risk couples (0.0015%) were required to receive prenatal diagnosis. We also found 53 cases of nondeletional-HPFH (nd-HPFH), including 52 with Italian nd-HPFH and one with the Aγ-197C-T heterozygous state. It is difficult to discriminate between Chinese Gγ(Aγδβ)0-thal and Italian nd-HPFH carriers using hemoglobin (Hb) analysis. Conclusions: This study is the first to describe the familial prevalence of HPFH/δβ-thalassemia and the high-risk rate in in Greater Guangzhou Area, and the findings will support the implementation of thalassemia screening for three common deletions by gap-PCR. We alsopresented a systematic description of genotype-phenotype relationships which will be useful for genetic counseling and prenatal diagnostic services for β-thalassemia intermedia.Keywords: Prevalence, δβ-thalassemia, HPFH, Guangzhou

The Problem of Borderline Hemoglobin A2 Levels in the Screening for β-Thalassemia Carriers in Sardinia

2016 ◽  
Vol 135 (4) ◽  
pp. 193-199 ◽  
Author(s):  
Maria Elisabetta Paglietti ◽  
Stefania Satta ◽  
Maria Carla Sollaino ◽  
Susanna Barella ◽  
Arianna Ventrella ◽  
...  
Keyword(s):  
Screening Program ◽  
Globin Gene ◽  
Routine Screening ◽  
Genetic Determinants ◽  
High Prevalence ◽  
Molecular Investigation ◽  
Gene Defects ◽  
Klf1 Gene ◽  
Hemoglobin A2

Background: The increase in HbA2 is the most important parameter for the identification of thalassemia carriers. However, in routine screening for hemoglobinopathies, some cases are difficult to classify because the level of HbA2 is not typically elevated. In this work, we report the results of a molecular investigation on a cohort of subjects with borderline HbA2. Methods: All subjects with a β-thalassemia carrier partner and a borderline percentage level of HbA2 were investigated for the presence of a pathological mutation in the β-globin gene. All negative subjects were screened for both the KLF1 mutation and the presence of ααα/ or αααα/ alleles. The subjects with reduced MCV and/or MCH were also screened for deletional and nondeletional α-globin gene defects. Results: Various β-globin mutations and KLF1 gene defects are the most common genetic determinants responsible for this phenotype in our population. Conclusion: KLF1 mutations are important in a screening program for hemoglobinopathies. An increase in HbF in association with borderline HbA2 levels is a useful but not exclusive marker that suggests the investigation of this gene. On the basis of our findings, we are able to suggest the molecular procedure to use in a population characterized by a high prevalence of thalassemia carriers.

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