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JAMA Network Open Oct 2023Sickle cell disease (SCD) is a monogenic disorder, yet clinical outcomes are influenced by additional genetic factors. Despite decades of research, the genetics of SCD... (Meta-Analysis)
Meta-Analysis
IMPORTANCE
Sickle cell disease (SCD) is a monogenic disorder, yet clinical outcomes are influenced by additional genetic factors. Despite decades of research, the genetics of SCD remain poorly understood.
OBJECTIVE
To assess all reported genetic modifiers of SCD, evaluate the design of associated studies, and provide guidelines for future analyses according to modern genetic study recommendations.
DATA SOURCES
PubMed, Web of Science, and Scopus were searched through May 16, 2023, identifying 5290 publications.
STUDY SELECTION
At least 2 reviewers identified 571 original, peer-reviewed English-language publications reporting genetic modifiers of human SCD phenotypes, wherein the outcome was not treatment response, and the comparison was not between SCD subtypes or including healthy controls.
DATA EXTRACTION AND SYNTHESIS
Data relevant to all genetic modifiers of SCD were extracted, evaluated, and presented following STREGA and PRISMA guidelines. Weighted z score meta-analyses and pathway analyses were conducted.
MAIN OUTCOMES AND MEASURES
Outcomes were aggregated into 25 categories, grouped as acute complications, chronic conditions, hematologic parameters or biomarkers, and general or mixed measures of SCD severity.
RESULTS
The 571 included studies reported on 29 670 unique individuals (50% ≤ 18 years of age) from 43 countries. Of the 17 757 extracted results (4890 significant) in 1552 genes, 3675 results met the study criteria for meta-analysis: reported phenotype and genotype, association size and direction, variability measure, sample size, and statistical test. Only 173 results for 62 associations could be cross-study combined. The remaining associations could not be aggregated because they were only reported once or methods (eg, study design, reporting practice) and genotype or phenotype definitions were insufficiently harmonized. Gene variants regulating fetal hemoglobin and α-thalassemia (important markers for SCD severity) were frequently identified: 19 single-nucleotide variants in BCL11A, HBS1L-MYB, and HBG2 were significantly associated with fetal hemoglobin (absolute value of Z = 4.00 to 20.66; P = 8.63 × 10-95 to 6.19 × 10-5), and α-thalassemia deletions were significantly associated with increased hemoglobin level and reduced risk of albuminuria, abnormal transcranial Doppler velocity, and stroke (absolute value of Z = 3.43 to 5.16; P = 2.42 × 10-7 to 6.00 × 10-4). However, other associations remain unconfirmed. Pathway analyses of significant genes highlighted the importance of cellular adhesion, inflammation, oxidative and toxic stress, and blood vessel regulation in SCD (23 of the top 25 Gene Ontology pathways involve these processes) and suggested future research areas.
CONCLUSIONS AND RELEVANCE
The findings of this comprehensive systematic review and meta-analysis of all published genetic modifiers of SCD indicated that implementation of standardized phenotypes, statistical methods, and reporting practices should accelerate discovery and validation of genetic modifiers and development of clinically actionable genetic profiles.
Topics: Humans; Fetal Hemoglobin; alpha-Thalassemia; Anemia, Sickle Cell; Genotype; Genetic Variation
PubMed: 37851445
DOI: 10.1001/jamanetworkopen.2023.37484 -
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 -
American Journal of Hematology Sep 2023This systematic literature review assessed the global prevalence and birth prevalence of clinically significant forms of alpha- and beta-thalassemia. Embase, MEDLINE,...
This systematic literature review assessed the global prevalence and birth prevalence of clinically significant forms of alpha- and beta-thalassemia. Embase, MEDLINE, and the Cochrane Library were searched for observational studies published January 1, 2000, to September 21, 2021. Of 2093 unique records identified, 69 studies reported across 70 publications met eligibility criteria, including 6 records identified from bibliography searches. Thalassemia prevalence estimates varied across countries and even within countries. Across 23 population-based studies reporting clinically significant alpha-thalassemia (e.g., hemoglobin H disease and hemoglobin Bart's hydrops fetalis) and/or beta-thalassemia (beta-thalassemia intermedia, major, and/or hemoglobin E/beta-thalassemia), prevalence estimates per 100 000 people ranged from 0.2 in Spain (over 2014-2017) to 27.2 in Greece (2010-2015) for combined beta- plus alpha-thalassemia; from 0.03 in Spain (2014-2017) to 4.5 in Malaysia (2007-2018) for alpha-thalassemia; and from 0.2 in Spain (2014-2017) to 35.7 to 49.6 in Iraq (2003-2018) for beta-thalassemia. Overall, the estimated prevalence of thalassemia followed the predicted pattern of being higher in the Middle East, Asia, and Mediterranean than in Europe or North America. However, population-based prevalence estimates were not found for many countries, and there was heterogeneity in case definitions, diagnostic methodology, type of thalassemia reported, and details on transfusion requirements. Limited population-based birth prevalence data were found. Twenty-seven studies reported thalassemia prevalence from non-population-based samples. Results from such studies likely do not have countrywide generalizability as they tended to be from highly specific groups. To fully understand the global prevalence of thalassemia, up-to-date, population-based epidemiological data are needed for many countries.
Topics: Pregnancy; Female; Humans; alpha-Thalassemia; beta-Thalassemia; Prenatal Diagnosis; Hydrops Fetalis; Asia; Hemoglobins, Abnormal
PubMed: 37357829
DOI: 10.1002/ajh.27006 -
EJHaem Jun 2024A recent evidence gaps assessment of the clinical, health-related quality of life, and economic burden associated with α-thalassemia is lacking. We conducted a...
A recent evidence gaps assessment of the clinical, health-related quality of life, and economic burden associated with α-thalassemia is lacking. We conducted a systematic literature review (SLR) following the methodological and reporting requirements of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the Cochrane Handbook for Systematic Reviews, using available literature over the past decade. This SLR identified a considerable evidence gap with regard to understanding the current burden of α-thalassemia as evident from paucity of studies published in the past 10 years. The limited data available still indicate that patients with α-thalassemia experience substantial morbidity and quality of life/economic burden that is generally comparable to patients with β-thalassemia.
PubMed: 38895066
DOI: 10.1002/jha2.882 -
International Journal of Molecular... May 2024Sickle cell nephropathy (SCN) is a common complication of sickle cell disease (SCD) that significantly contributes to morbidity and mortality. In addition to clinical... (Review)
Review
Sickle cell nephropathy (SCN) is a common complication of sickle cell disease (SCD) that significantly contributes to morbidity and mortality. In addition to clinical and life-style factors, genetic variants influence this risk. We performed a systematic review, searching five databases. Studies evaluating the effect of genetic modifiers on SCN were eligible. Twenty-eight studies (fair-to-good quality) were included: one genome-wide association study, twenty-six case-control studies, and one article combining both approaches. was significantly associated with albuminuria and hyperfiltration in children and with worse glomerular filtration in adults. On the other hand, alpha-thalassemia protected patients against albuminuria and hyperfiltration, while variants were protective against albuminuria alone. The long GT-tandem repeat polymorphism led to a lower glomerular filtration rate. No modifiers for the risk of hyposthenuria were identified. A genome-wide association approach identified three new loci for proteinuria (, , and ) and nine loci were linked with eGFR (, , , , , , , , and ). In conclusion, this systematic review supports the role of genetic modifiers in influencing the risk and progression of SCN. Incorporating and expanding this knowledge is crucial to improving the management and clinical outcomes of patients at risk.
Topics: Humans; Anemia, Sickle Cell; Genome-Wide Association Study; Genetic Predisposition to Disease; Kidney Diseases; Apolipoprotein L1; Disease Progression; Genes, Modifier; Glomerular Filtration Rate
PubMed: 38791464
DOI: 10.3390/ijms25105427 -
Reviews on Recent Clinical Trials May 2024β-thalassemia imposes significant complications on affected patients. Silymarin, a natural flavonoid complex, has potential therapeutic properties.
BACKGROUND
β-thalassemia imposes significant complications on affected patients. Silymarin, a natural flavonoid complex, has potential therapeutic properties.
OBJECTIVE
This systematic review aims to comprehensively evaluate the literature on the mechanistic effects of Silymarin on β-thalassemia outcomes in children and adolescents.
METHODS
A systematic search of electronic databases, including MEDLINE/PubMed, Embase, Scopus, Cochrane Library, and Web of Science (WOS), was done to identify relevant clinical trials before January 2024. Various data were extracted, including study characteristics, outcomes measured (hematological parameters, oxidative stress markers, iron metabolism, and other outcomes), proposed mechanisms, and safety.
RESULTS
By iron chelation effects, Silymarin can reduce reactive oxygen species (ROS) production, increase intracellular antioxidant enzyme glutathione (GSH), and insert antioxidant effects. It also attenuated inflammation through reduced tumor necrosis factor-alpha (TNF-α), transforming growth factor-β1 (TGF-β1), interferon-gamma (IFNγ), C-reactive protein (CRP), interleukin 6 (IL-6), IL-17, and IL-23 levels and increase in IL-4 and IL-10 levels. By reducing iron overload conditions, Silymarin indicates modulatory effects on immune abnormalities, inhibits red blood cell (RBC) hemolysis, increases RBC count, and minimizes the need for a transfusion. Moreover, it reduces myocardial and hepatic siderosis, improves liver function tests, and modifies abnormal enzymes, particularly for aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), total bilirubin, and total protein levels. Silymarin also reduces iron overload, increases antioxidant and anti-inflammatory capacity in cardiomyocytes, and reveals antioxidant effects.
CONCLUSION
Silymarin indicates promising effects on various aspects of children and adolescents with β-thalassemia and has no serious side effects on the investigated dosage.
PubMed: 38818907
DOI: 10.2174/0115748871305325240511122602 -
American Journal of Medical Genetics.... May 2024RASopathies are a group of malformation syndromes known to lead to nonimmune hydrops fetalis (NIHF) in severe presentations. Pathogenic variants can be de novo or... (Meta-Analysis)
Meta-Analysis Review
RASopathies are a group of malformation syndromes known to lead to nonimmune hydrops fetalis (NIHF) in severe presentations. Pathogenic variants can be de novo or parentally inherited. Despite being a known frequent presentation, the fraction of monogenic NIHF cases due to RASopathies is limited in the literature. Also, the specific parental contribution of RASopathies to NIHF is not well described. Our objective was to review pooled exome sequencing (ES) diagnostic yield of RASopathies for NIHF and to determine the parental contribution of RASopathy to NIHF. We performed a systematic review of prenatal ES studies from January 1, 2000 to August 1, 2022. Thirty-six studies met inclusion criteria. Cases with RASopathy gene variants were reviewed. NIHF cases were further classified as isolated or non-isolated. Thirty-six ES studies including 46 pregnancies with NIHF and a diagnosed RASopathy were reviewed. Forty-four diagnostic variants and 2 variants of uncertain significance in 12 RASopathy genes were identified. Expanding on what was previously published, a total of 506 NIHF cases were extracted with 191 cases yielding a positive diagnosis by ES. The overall rate of RASopathy diagnosis in clinically diagnosed NIHF cases was 9% (44/506). The rate of RASopathy diagnosis among NIHF cases with positive genetic diagnosis by ES was 23% (44/191). Of the 46 cases identified, 13 (28%) variants were parentally inherited; specifically, 5/13 (38%) maternal, 3/13 (23%) paternal, 2/13 (15%) biparental, and 3/13 (23%) unspecified. Majority of NIHF cases 29/46 (63%) were isolated. Among NIHF cases with positive ES diagnoses, RASopathy diagnostic yield by ES was 23%. NIHF secondary to RASopathies was parentally inherited in 28% of cases. Most cases of NIHF due to RASopathy were isolated, with no prenatal detection of associated anomalies.
Topics: Pregnancy; Male; Female; Humans; Hydrops Fetalis; Exome Sequencing; Fathers
PubMed: 38156365
DOI: 10.1002/ajmg.a.63494 -
Prenatal Diagnosis Nov 2023To clarify the relevance of PIEZO1 variants detected by prenatal exome in the context of non-immune hydrops fetalis (NIHF).
OBJECTIVE
To clarify the relevance of PIEZO1 variants detected by prenatal exome in the context of non-immune hydrops fetalis (NIHF).
METHODS
A systematic review of prenatal exome studies from 1/1/2000-8/1/2022 was performed. Thirty-six studies met the inclusion criteria. PIEZO1 variants were categorized by disease mode (dominant (AD) versus recessive (AR)) and classified by the American College of Medical Genetics and Genomics (ACMG) guidelines.
RESULTS
Twenty-two pregnancies with 35 distinct PIEZO1 variants were included. We deemed PIEZO1 variants to be "likely diagnostic" in 12/22 pregnancies, "possibly diagnostic" in 7/22, and "unlikely diagnostic" in 3/22. In total, 19 of 191 NIHF cases diagnosed by prenatal exome were attributed to PIEZO1. Among likely diagnosed cases, the disease mode was AR in eight and AD in four. PIEZO1 variants causing AR NIHF were characterized by loss of function and isolated NIHF phenotype. PIEZO1 variants causing AD NIHF were characterized by gain of function in red blood cells, scarcity in databases, and sporadic inheritance. Missense variants associated with NIHF were clustered in three domains: transmembrane helical unit 4 (THU4), THU5, and the Cap.
CONCLUSION
PIEZO1 variants were reported in 10% of NIHF cases diagnosed by prenatal exome, making PIEZO1 the most common single gene reported in NIHF.
Topics: Pregnancy; Female; Humans; Hydrops Fetalis; Exome Sequencing; Genomics; Ion Channels
PubMed: 37902181
DOI: 10.1002/pd.6451 -
Prenatal Diagnosis Nov 2023Several factors associated with poor outcome in patients with prenatally diagnosed sacrococcygeal teratoma (SCT) have been found. However, the prognostic accuracy of... (Meta-Analysis)
Meta-Analysis Review
Several factors associated with poor outcome in patients with prenatally diagnosed sacrococcygeal teratoma (SCT) have been found. However, the prognostic accuracy of these factors has not been well established. Therefore, we aimed to systematically review the prognostic accuracy of factors associated with poor outcome in these patients. We queried Search Premier, COCHRANE Library, EMCARE, EMBASE, PubMed, ScienceDirect, and Web of Science databases to identify studies regarding patients with prenatally diagnosed SCT. Poor outcome was defined as termination of pregnancy (TOP), intrauterine fetal death (IUFD), or perinatal death. We estimated the odds ratio of factors associated with poor outcome. Eleven studies (447 patients) were included. Overall mortality, including TOP, was 34.9%. Factors associated with poor outcome in fetuses with prenatally diagnosed SCT were cardiomegaly, hypervascular tumor, solid tumor morphology, fetal hydrops, and placentomegaly. A tumor volume to fetal weight ratio (TFR) of >0.12 before a gestational age of 24 weeks is predictive of poor outcome. The prognostic accuracy of factors associated with poor outcome in fetuses prenatally diagnosed with SCT seems promising. Factors associated with cardiac failure such as cardiomegaly, hypervascular tumor, solid tumor morphology, fetal hydrops, placentomegaly, and TFR >0.12 were found to be predictive of poor outcome.
Topics: Pregnancy; Female; Humans; Infant; Prognosis; Hydrops Fetalis; Ultrasonography, Prenatal; Teratoma; Cardiomegaly; Sacrococcygeal Region
PubMed: 37964422
DOI: 10.1002/pd.6457 -
Hemoglobin Mar 2024Sickle cell anemia (SCA) is the most common cause of stroke in children. As it is a rare disease, studies investigating the association with complications like stroke in... (Meta-Analysis)
Meta-Analysis
Sickle cell anemia (SCA) is the most common cause of stroke in children. As it is a rare disease, studies investigating the association with complications like stroke in SCD have small sample sizes. Here, we performed a systematic review and meta-analysis of the studies exploring an association of genetic variants with stroke to get a better indication of their association with stroke. PubMed and Google Scholar were searched to identify studies that had performed an association analysis of genetic variants for the risk of stroke in SCA patients. After screening of eligible studies, summary statistics of association analysis with stroke and other general information were extracted. Meta-analysis was performed using the fixed effect method on the tool METAL and forest plots were plotted using the R program. The random effect model was performed as a sensitivity analysis for loci where significant heterogeneity was observed. 407 studies were identified using the search term and after screening 37 studies that cumulatively analyzed 11,373 SCA patients were included. These 37 studies included a total of 2,222 SCA patients with stroke, predominantly included individuals of African ancestry (N = 16). Three of these studies performed whole exome sequencing while 35 performed single nucleotide-based genotyping. Though the studies reported association with 132 loci, meta-analyses could be performed only for 12 loci that had data from two or more studies. After meta-analysis we observed that four loci were significantly associated with risk for stroke: -α3.7 kb ( = 0.00000027), rs489347- ( = 0.00081), rs2238432-9 ( = 0.00085), rs11853426- ( = 0.0034), and rs1800629- ( = 0.0003396). Ethnic representation of regions with a high prevalence of SCD like the Mediterranean basin and India needs to be improved for genetic studies on associated complications like stroke. Larger genome-wide collaborative studies on SCD and associated complications including stroke need to be performed.
Topics: Anemia, Sickle Cell; Humans; Stroke; Genetic Predisposition to Disease; Genetic Variation; Polymorphism, Single Nucleotide; Risk Factors
PubMed: 38637280
DOI: 10.1080/03630269.2024.2340685