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[Rinsho Ketsueki] the Japanese Journal... 2021Thalassemia is caused by a reduced production of one globin chain due to a quantitative imbalance between the α-globin and non-α-globin chains that make up the...
Thalassemia is caused by a reduced production of one globin chain due to a quantitative imbalance between the α-globin and non-α-globin chains that make up the hemoglobin. It is classified into α- and β-thalassemia and characterized by microcytosis with polycythemia, and a Mentzer index of ≤13 aids in the diagnosis. In the genetic analysis of α-thalassemia, the Southeast Asian type was found to be the most common genetic subtype among Japanese and non-Japanese without a substantial difference. Conversely, the genetic analysis of β-thalassemia revealed differences in the types and frequencies of mutations between Japanese individuals and foreigners living in Japan, with Japanese-specific mutations such as -31 A→G (TATA box). Acquired α-thalassemia exists in exceptional cases, and cases of myelodysplastic syndrome with acquired Hemoglobin H disease have been reported as α-thalassemia myelodysplastic syndrome. Recent trials using a novel therapeutic agent, luspatercept, for transfusion-dependent β-thalassemia revealed that luspatercept safely and significantly reduces the transfusion volume.
Topics: Blood Transfusion; Humans; Japan; Mutation; alpha-Thalassemia; beta-Thalassemia
PubMed: 34497231
DOI: 10.11406/rinketsu.62.914 -
Hemoglobin Jan 2022The island nation of Sri Lanka with 22 million people (in 2020) has an estimated 2000 patients with severe thalassemia. The majority have β-thalassemia (β-thal) major... (Review)
Review
The island nation of Sri Lanka with 22 million people (in 2020) has an estimated 2000 patients with severe thalassemia. The majority have β-thalassemia (β-thal) major (β-TM), and Hb E (: c.79G>A)/β-thal accounts for most of the remainder. Carrier rate for α-thalassemia (α-thal) trait is 9.9% and β-thal trait is 2.5%, with very similar rates in the three major ethnic groups (Sinhalese, Tamils and Moors). The distribution of thalassemia type reveals a remarkable variation, even in this small island, mirroring historical distribution of malaria. Even though healthcare is provided free by the state including blood transfusions and chelation, the overall survival of patients of β-TM is still not on a par with that of the Mediterranean countries. A national thalassemia prevention program was set up in 2007, but overall success of the exercise based essentially on dissuasion of marriages is not very promising.
Topics: Humans; Phenotype; Sri Lanka; alpha-Thalassemia; beta-Thalassemia
PubMed: 35950586
DOI: 10.1080/03630269.2022.2025826 -
The New England Journal of Medicine Jun 2021
Topics: Female; Humans; Pregnancy; Prenatal Diagnosis; alpha-Thalassemia; beta-Thalassemia
PubMed: 34077655
DOI: 10.1056/NEJMc2105064 -
The New England Journal of Medicine Jun 2021
Topics: Female; Humans; Pregnancy; Prenatal Diagnosis; alpha-Thalassemia; beta-Thalassemia
PubMed: 34077656
DOI: 10.1056/NEJMc2105064 -
Orphanet Journal of Rare Diseases Jun 2020Defective synthesis of the α-globin chain due to mutations in the alpha-globin genes and/or its regulatory elements leads to alpha thalassaemia syndrome. Complete... (Review)
Review
BACKGROUND
Defective synthesis of the α-globin chain due to mutations in the alpha-globin genes and/or its regulatory elements leads to alpha thalassaemia syndrome. Complete deletion of the 4 alpha-globin genes results in the most severe phenotype known as haemoglobin Bart's, which leads to intrauterine death. The presence of one functional alpha gene is associated with haemoglobin H disease, characterised by non-transfusion-dependent thalassaemia phenotype, while silent and carrier traits are mostly asymptomatic.
MAIN BODY
Clinical manifestations of non-deletional in alpha thalassaemia are varied and have more severe phenotype compared to deletional forms of alpha thalassaemia. Literature for the molecular mechanisms of common non-deletional alpha thalassaemia including therapeutic measures that are necessarily needed for the understanding of these disorders is still in demand. This manuscript would contribute to the better knowledge of how defective production of the α-globin chains due to mutations on the alpha-globin genes and/or the regulatory elements leads to alpha thalassaemia syndrome.
CONCLUSION
Since many molecular markers are associated with the globin gene expression and switching over during the developmental stages, there is a need for increased awareness, new-born and prenatal screening program, especially for countries with high migration impact, and for improving the monitoring of patients with α-thalassaemia.
Topics: Female; Gene Expression; Humans; Mutation; Phenotype; Pregnancy; alpha-Globins; alpha-Thalassemia
PubMed: 32600445
DOI: 10.1186/s13023-020-01429-1 -
International Journal of Molecular... Sep 2022Thalassemia is the most common genetic disorder worldwide. Thalassemia intermedia (TI) is non-transfusion-dependent thalassemia (NTDT), which includes β-TI hemoglobin,... (Review)
Review
Thalassemia is the most common genetic disorder worldwide. Thalassemia intermedia (TI) is non-transfusion-dependent thalassemia (NTDT), which includes β-TI hemoglobin, E/β-thalassemia and hemoglobin H (HbH) disease. Due to the availability of iron chelation therapy, the life expectancy of thalassemia major (TM) patients is now close to that of TI patients. Iron overload is noted in TI due to the increasing iron absorption from the intestine. Questions are raised regarding the relationship between iron chelation therapy and decreased patient morbidity/mortality, as well as the starting threshold for chelation therapy. Searching all the available articles up to 12 August 2022, iron-chelation-related TI was reviewed. In addition to splenectomized patients, osteoporosis was the most common morbidity among TI cases. Most study designs related to ferritin level and morbidities were cross-sectional and most were from the same Italian study groups. Intervention studies of iron chelation therapy included a subgroup of TI that required regular transfusion. Liver iron concentration (LIC) ≥ 5 mg/g/dw measured by MRI and ferritin level > 300 ng/mL were suggested as indicators to start iron chelation therapy, and iron chelation therapy was suggested to be stopped at a ferritin level ≤ 300 ng/mL. No studies showed improved overall survival rates by iron chelation therapy. TI morbidities and mortalities cannot be explained by iron overload alone. Hypoxemia and hemolysis may play a role. Head-to-head studies comparing different treatment methods, including hydroxyurea, fetal hemoglobin-inducing agents, hypertransfusion as well as iron chelation therapy are needed for TI, hopefully separating β-TI and HbH disease. In addition, the target hemoglobin level should be determined for β-TI and HbH disease.
Topics: Ferritins; Humans; Iron; Iron Chelating Agents; Iron Overload; alpha-Thalassemia; beta-Thalassemia
PubMed: 36077584
DOI: 10.3390/ijms231710189 -
The New England Journal of Medicine Jun 2021
Topics: Humans; alpha-Thalassemia; beta-Thalassemia
PubMed: 34077657
DOI: 10.1056/NEJMc2105064 -
American Journal of Obstetrics &... Sep 2023This study aimed to review the diagnostic criteria for mirror syndrome and describe its clinical presentation. (Review)
Review
OBJECTIVE
This study aimed to review the diagnostic criteria for mirror syndrome and describe its clinical presentation.
DATA SOURCES
Databases from PubMed, Scopus, Cochrane Library, ClinicalTrials.gov, and CINAHL were inquired for case series containing ≥2 cases of mirror syndrome from inception to February 2022.
STUDY ELIGIBILITY CRITERIA
Studies were included if they reported ≥2 cases of mirror syndrome and included case reports, case series, cohort studies, and case-control studies.
STUDY APPRAISAL AND SYNTHESIS METHODS
The studies' quality and risk of bias were independently assessed. Data were tabulated using Microsoft Excel and summarized using narrative review and descriptive statistics. This systematic review was conducted according to the Preferred Reporting Item for Systematic Reviews and Meta-Analyses statement. All eligible references were assessed. Screening of records and data extraction were independently performed, and a third author resolved disagreements.
RESULTS
Of 13 citations, 12 studies (n=82) reported diagnostic criteria for mirror syndrome: maternal edema (11/12), fetal hydrops (9/12), placental edema (6/12), placentomegaly (5/12), and preeclampsia (2/12); 12 studies (n=82) described the clinical presentation of mirror syndrome as maternal edema (62.2%), hypoalbuminemia (54.9%), anemia (39.0%), and new-onset hypertension (39.0%); 4 studies (n=36) reported that hemodilution was present in all patients; 8 studies (n=36) reported the etiology of fetal hydrops, with the most common being structural cardiac malformations (19.4%), alpha thalassemia (19.4%), Rh isoimmunization (13.9%), and nonimmune hydrops fetalis (13.9%); and 6 studies (n=47) reported maternal complications, 89.4% of which were major: postpartum hemorrhage (44.7%), hemorrhage requiring blood transfusion (19.1%), intensive care unit admission (12.8%), heart failure (10.6%), pulmonary edema (8.5%), and renal dysfunction (8.5%). In 39 cases, the reported fetal outcomes were stillbirth (66.6%) and neonatal or infant death (25.6%). The overall survival rate among continued pregnancies was 7.7%.
CONCLUSION
The diagnostic criteria of mirror syndrome differed considerably among studies. Mirror syndrome clinical presentation overlapped with preeclampsia. Only 4 studies discussed hemodilution. Significant maternal morbidity and fetal mortality were associated with mirror syndrome. Further research is warranted to elucidate the pathogenesis of mirror syndrome to better guide clinicians in identifying and managing the condition.
Topics: Female; Humans; Infant, Newborn; Pregnancy; Edema; Hydrops Fetalis; Placenta; Pre-Eclampsia; Syndrome; Systematic Reviews as Topic
PubMed: 37385374
DOI: 10.1016/j.ajogmf.2023.101067 -
Hematology (Amsterdam, Netherlands) Dec 2022The 3.7 kb deletion (-α) in the α-globin cluster, which characterizes α-thalassemia, has been reported to have a carrier rate of 4.78% in southern China. Three -α...
OBJECTIVE
The 3.7 kb deletion (-α) in the α-globin cluster, which characterizes α-thalassemia, has been reported to have a carrier rate of 4.78% in southern China. Three -α subtypes have been identified worldwide. However, the -α subtype has not previously been identified in China. Herein, we reported identification of the -α subtype in a Chinese patient.
METHODS
We used gap-PCR and a liquid chip system to detect α-thalassemia mutations. Multiple ligation-dependent probe amplification was performed to detect the large deletion. We finally used Sanger sequencing and single molecule real-time sequencing to characterize and confirm the genotype.
RESULTS
The proband, characterized as -α heterozygous, showed microcytosis and hypochromic red cells, with a mean corpuscular volume of 78 fL and mean corpuscular hemoglobin of 25.4 pg. The proband's mutation was inherited from her father, who had normal blood parameters.
CONCLUSION
We first identified the -α subtype in China. Consequently, all -α subtypes have now been identified in the Chinese population. Therefore, attention should be paid to -α in clinical prenatal diagnosis, given that commonly used methods such as gap-PCR may lead to misdiagnosis or missed diagnosis.
Topics: China; Female; Genotype; Heterozygote; Humans; Pregnancy; alpha-Globins; alpha-Thalassemia
PubMed: 35916627
DOI: 10.1080/16078454.2022.2101913 -
BMC Medical Genetics Aug 2020The 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...
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 (αα/α α) in 33.3% of the samples, followed by heterozygosity (αα/α α) for the same mutation in 32.3%. PA-1 was therefore the most frequent allele (0.59). The frequency of the α (--) allele was 0.017. Rare alleles that were found in very low frequencies included α (--) 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 (β4 tetramer) disease phenotype. The α (-) allele is also encountered, which has implications for premarital counseling, especially for the possibility of having babies with alpha thalassemia major (Barts hydrops fetalis).
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Alleles; Child; Child, Preschool; Female; Gene Frequency; Genotype; Humans; Infant; Infant, Newborn; Kuwait; Male; Middle Aged; Retrospective Studies; Young Adult; alpha-Globins; alpha-Thalassemia
PubMed: 32831051
DOI: 10.1186/s12881-020-01105-y