Twin-twin transfusion syndrome remains a major cause of morbidity and mortality in monochorionic twin pregnancies, arising from placental vascular anastomoses and representing a frequent indication for referral to fetal therapy centers. Despite advances in ultrasound assessment and fetoscopic laser therapy, variability in diagnostic thresholds, Doppler interpretation, and recognition of overlapping phenotypes-particularly twin anemia-polycythemia sequence and selective fetal growth restriction-continues to complicate clinical decision-making and limits meaningful comparison of outcomes across centers. Differences in the definition of polyhydramnios further contribute to this inconsistency, as traditional staging criteria remain widely applied, whereas gestational age-specific thresholds are commonly used in international studies. This expert review synthesizes current evidence regarding the placental vascular basis of twin-twin transfusion syndrome and related monochorionic phenotypes, including overlap phenotypes, and examines the evolution of diagnostic definitions, Doppler assessment, and treatment strategies. Ongoing uncertainty remains, particularly regarding prognostic heterogeneity in advanced-stage disease. This variability may partly reflect heterogeneous Doppler abnormalities grouped within the same stage, as well as by overlap phenotypes involving twin anemia-polycythemia sequence and selective fetal growth restriction. An evidence-informed framework is presented that integrates placental vascular anatomy, Doppler findings, and overlap phenotypes with Quintero staging to improve interpretation and promote consistency in classification and clinical communication. Developed before the broader recognition of overlap phenotypes and contemporary approaches to Doppler and amniotic fluid assessment, the staging system continues to provide a structural foundation that can be interpreted in the context of emerging evidence. The proposed framework preserves that foundation while refining interpretation in light of evolving understanding of disease heterogeneity and overlap phenotypes. It is intended as a complementary and hypothesis-generating approach rather than a prescriptive management system; prospective validation is required.

Bone marrow failure syndromes (BMFS) encompass a spectrum of acquired and constitutional disorders characterized by impaired hematopoiesis and cytopenias. In pediatric patients, constitutional BMFS represent up to 50% of cases, yet their diagnosis remains challenging due to subtle or absent extra-hematologic manifestations that mimic immune aplastic anemia. Accurate differentiation is essential, as it directly influences prognosis, therapeutic strategy, surveillance for extra-hematopoietic complications, and donor selection for hematopoietic cell transplantation. This review presents a structured diagnostic framework for pediatric BMFS, integrating clinical history, physical examination, bone marrow morphology, flow cytometry, cytogenetic analysis, disease-specific functional assays, and next-generation sequencing (NGS). Chromosomal breakage testing remains the gold-standard assay for Fanconi anemia, while telomere length measurement is the strongest predictor for differentiating constitutional from immune BMF. NGS enables comprehensive germline variant detection, resolves diagnostically ambiguous presentations, and informs genotype-guided familial screening. Recognition of disease-specific patterns of clonal hematopoiesis further refines diagnostic precision and risk stratification. A stepwise, evidence-based approach is essential to optimize early diagnosis and long-term outcomes in pediatric patients with BMFS.

Fanconi anemia (FA) is a genetic disorder characterized by aplastic anemia and bone marrow failure arising from DNA crosslinking repair deficiencies. During hematopoietic differentiation, formaldehyde accumulates as a byproduct of transcriptional reprogramming, generating DNA crosslinks that abort differentiation and progressively deplete the hematopoietic hierarchy in the absence of FA pathway function. We performed a systematic screen of the aldehyde dehydrogenase (ALDH) activities to identify enzymes capable of metabolizing endogenous formaldehyde and protecting hematopoiesis in FA mutant cells. Our results identify ALDH8A1 as an effective enzyme that ameliorates formaldehyde-induced DNA damage during hematopoietic differentiation. Enhanced formaldehyde clearance significantly reduces DNA damage, markedly improving the survival of differentiating FA mutant progenitor cells and enabling completion of lineage progression. These findings highlight enhanced formaldehyde metabolism as an effective approach to ameliorate endogenous genotoxicity in FA mutant blood cells, suggesting a potential therapeutic strategy for restoring sustained hematopoiesis in patients with FA.

Sickle cell disease (SCD) is an inherited hemoglobinopathy caused by a point mutation in the β-globin gene, resulting in hemoglobin S polymerization under hypoxic conditions. This process leads to erythrocyte dehydration, impaired deformability, hemolysis, and recurrent vaso-occlusion, which may culminate in acute painful crises and progressive organ damage. Hepatic involvement is a recognized but underreported complication of SCD and can range from mild biochemical abnormalities to life-threatening hepatic vaso-occlusive crisis (VOC). This case report presents a 25-year-old woman, with homozygous sickle cell anemia who developed a rapidly progressive hepatic VOC following a mild respiratory illness. Her clinical course was marked by acute abdominal pain, severe transaminitis, cholestasis, escalating transfusion requirements, and radiologic evidence of hepatomegaly. Clinical and biochemical improvement was observed following a multimodal management approach that included supportive care, corticosteroids, blood transfusion, and the addition of intravenous metronidazole. This case highlights hepatic VOC as a serious manifestation of SCD and explores the potential role of metronidazole as an adjunctive therapy, given its immunomodulatory and anti-inflammatory properties. Further investigation is warranted to clarify its therapeutic role in sickle cell-related vaso-occlusive complications.

β-thalassemia minor, often referred to as the β-thalassemia trait, is among the most prevalent hemoglobinopathies globally, impacting around 80-90 million carriers, with a prevalence of up to 15% among Mediterranean, Middle Eastern, and Asian populations. Although traditionally regarded as clinically benign, pregnancy imposes hematologic and metabolic stressors that may unmask latent vulnerabilities. This review combines the latest data and findings about the pathophysiology of β-thalassemia minor during pregnancy, its short-term outcomes on the mother and fetus, and its long-term impact on the child, as well as management techniques. A narrative review of PubMed-indexed studies (2000-2025) was conducted, including cohort and case-control studies, systematic reviews, meta-analyses, and international guidelines. Outcomes were organized by theme, and quantitative findings (prevalence, relative risks, odds ratios) were combined when available. Anemia is a common health issue for mothers. Literature mentions that the pooled incidence is between 30% and 40% during the third trimester, with ~5%of carriers needing a blood transfusion (mainly in iron-deficient or baseline Hb 6-8 g/dL cases). Meta-analyses have shown elevated risks of pre-eclampsia (odds ratio (OR) ~ 1.4, 95% confidence interval (CI) 1.1-1.8) and postpartum hemorrhage (PPH); however, estimates differ by region. The odds of preterm delivery (OR ~ 1.4), small-for-gestational-age (SGA) (OR ~ 1.5), and low birth weight (LBW) are slightly increased for carriers, and neonatal intensive care unit (NICU) admission rates are also higher for carriers. However, the risk of stillbirth is not always increased. The usual approach is iron supplementation guided by ferritin levels to prevent overload, personalized transfusion thresholds, and regular folate support. There is not much evidence for long-term consequences for children of carrier mothers since no research has followed more than 200 children born to carrier mothers into adulthood. However, maternal anemia is linked to slower growth, neurodevelopmental issues, and a higher risk of cardiometabolic problems in larger groups of pregnant women. However, maternal anemia is associated with slower growth, neurodevelopment, and higher cardiometabolic risk in larger groups of pregnant women. β-thalassemia minor during pregnancy usually has a mild, though significant, impact. While most pregnancies proceed without complications, this condition is associated with a significantly higher prevalence of anemia and other adverse postnatal outcomes. Consequently, the implementation of risk-stratified monitoring, smart supplementation, and standardized management protocols is essential. Prospective registries, mechanistic placental research, and long-term offspring cohorts are necessary to better understand long-term trends.

Unstable hemoglobin variants are rare structural hemoglobin disorders in which alterations in the globin chain reduce hemoglobin stability, promoting denaturation, precipitation, and red cell injury. Affected individuals may present with a broad spectrum, ranging from compensated hemolysis to severe transfusion-dependent anemia, and episodes are commonly exacerbated by intercurrent illness or oxidative stress. Diagnosis remains challenging because many unstable variants are not readily recognized by routine hemoglobin separation, and classic morphological clues (Heinz bodies; bite/blister cells) are neither uniformly present nor specific. This review summarizes the molecular mechanisms underlying hemoglobin instability, outlines phenotypic patterns across the lifespan (including neonatal-limited instability involving fetal hemoglobin), and provides a practical diagnostic framework that integrates hemoglobin separation methods, stability assays, and molecular testing. Supportive care, including avoidance of oxidant triggers, folate supplementation, and transfusion support when needed, remains the mainstay, while splenectomy and curative transplantation are reserved for selected severe cases.