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Down syndrome (DS) is defined by an extra copy of chromosome 21 and confers an increased susceptibility to hematological disorders. Transient abnormal myelopoiesis (TAM) and myeloid‐leukemia associated with Down syndrome (ML‐DS) are two conditions that need to be accurately diagnosed to provide appropriate management. Both TAM and ML‐DS are characterized by proliferation of megakaryoblasts carrying a mutation in the GATA1 gene. Here, we report four cases with educational significance, highlighting typical diagnostic features that facilitate the differentiation between these two conditions, thereby assisting clinicians and medical laboratory professionals in effectively managing and monitoring these patients. [ABSTRACT FROM AUTHOR]

Background: Congenital malignancies are unusual fetal conditions, and therefore, the data on their prenatal manifestation are limited. Transient abnormal myelopoiesis (TAM) is a hematologic disorder characteristic for babies with trisomy 21 and based on the transient appearance of blast cells in peripheral blood. Methods: This paper presents prenatal manifestation of congenital TAM in a newborn with normal karyotype and reviews the literature on prenatal manifestation of this disorder. Results: A pregnant woman in her third pregnancy referred herself to the hospital for reduced fetal movements at 30 weeks of gestation. Admission's ultrasound scan showed an increased middle cerebral artery peak systolic velocity together with hepatomegaly. The patient was admitted to the labor ward for cardiotocography monitoring which showed acute fetal distress with repeated unprovoked decelerations. An emergency cesarean section was conducted and a phenotypically normal female newborn with low Apgar score was delivered. Further examination of the peripheral blood revealed anemia and leukocytosis with high blast proportion. A bone marrow aspirate revealed 70.2% of blasts in a sample with an abnormal karyotype of 47 XX+21. Cytogenetic analysis of the blasts with later microarray comparative genomic hybridization confirmed the presence of GATA1 mutation. However, the buccal smear showed a normal karyotype in the infant. The disease was classified as TAM. Conclusions: Our study demonstrates a rare case of prenatal manifestation of TAM in a neonate with a normal karyotype. Obstetricians should pay attention to symptoms like high MCA PSV and hepatosplenomegaly as possible causes of fetal hematological disorders and differentiate it with infection or isoimmunization. [ABSTRACT FROM AUTHOR]

Abstract Background Down syndrome myeloid hyperplasia includes transient abnormal myelopoiesis (TAM) and the myeloid leukemia associated with Down syndrome (ML-DS). The mutation of GATA1 gene is essential in the development of Down syndrome combined with TAM or ML-DS. Some patients with TAM are asymptomatic and may also present with severe manifestations such as hepatosplenomegaly and hydrops. Case presentation We report two cases of prenatally diagnosed TAM. One case was a rare placental low percentage 21 trisomy mosiacism, resulting in the occurrence of a false negative NIPT. The final diagnosis was made at 36 weeks of gestation when ultrasound revealed significant enlargement of the foetal liver and spleen and an enlarged heart; the foetus eventually died in utero. We detected a placenta with a low percentage (5–8%) of trisomy 21 mosiacism by Copy Number Variation Sequencing (CNV-seq) and Fluorescence in situ hybridization (FISH). In another case, foetal oedema was detected by ultrasound at 31 weeks of gestation. Two foetuses were diagnosed with Down syndrome by chromosomal microarray analysis via umbilical vein puncture and had significantly elevated cord blood leucocyte counts with large numbers of blasts. The GATA1 Sanger sequencing results suggested the presence of a [NM_002049.4(GATA1):c.220G > A (p. Val74Ile)] hemizygous variant and a [NM_002049.4(GATA1):c.49dupC(p. Gln17ProfsTer23)] hemizygous variant of the GATA1 gene in two cases. Conclusion It seems highly likely that these two identified mutations are the genetic cause of prenatal TAM in foetuses with Down syndrome.

Background: Down syndrome myeloid hyperplasia includes transient abnormal myelopoiesis (TAM) and the myeloid leukemia associated with Down syndrome (ML-DS). The mutation of GATA1 gene is essential in the development of Down syndrome combined with TAM or ML-DS. Some patients with TAM are asymptomatic and may also present with severe manifestations such as hepatosplenomegaly and hydrops. Case presentation: We report two cases of prenatally diagnosed TAM. One case was a rare placental low percentage 21 trisomy mosiacism, resulting in the occurrence of a false negative NIPT. The final diagnosis was made at 36 weeks of gestation when ultrasound revealed significant enlargement of the foetal liver and spleen and an enlarged heart; the foetus eventually died in utero. We detected a placenta with a low percentage (5–8%) of trisomy 21 mosiacism by Copy Number Variation Sequencing (CNV-seq) and Fluorescence in situ hybridization (FISH). In another case, foetal oedema was detected by ultrasound at 31 weeks of gestation. Two foetuses were diagnosed with Down syndrome by chromosomal microarray analysis via umbilical vein puncture and had significantly elevated cord blood leucocyte counts with large numbers of blasts. The GATA1 Sanger sequencing results suggested the presence of a [NM_002049.4(GATA1):c.220G > A (p. Val74Ile)] hemizygous variant and a [NM_002049.4(GATA1):c.49dupC(p. Gln17ProfsTer23)] hemizygous variant of the GATA1 gene in two cases. Conclusion: It seems highly likely that these two identified mutations are the genetic cause of prenatal TAM in foetuses with Down syndrome. [ABSTRACT FROM AUTHOR]

Simple Summary: Patients with Down Syndrome have been thoroughly studied over the past 100 years, and many attempts have been made to attain insight into the developmental biology of DS. Given the association of DS with several hematological disorders, it was more than appealing to us to conduct a literature research to identify the rare subtype of acute myeloid leukemias associated with DS -Myeloid Leukemia of Down Syndrome- to investigate its occurrence, clinical presentation, and typical characteristics in terms of blast morphology and immunophenotype, and suggest optimal criteria for early diagnosis and progression monitoring. Among others, the multistep clonal evolution process is being analyzed here, while challenges on treatment of those patients are presented in detail. We suggested that a standardized holistic approach of care for children with Myeloid Leukemia of Down Syndrome should be ensured and applied to provide more enhanced outcomes to those patients. Myeloid leukemia of Down syndrome (ML-DS) is characterized by a distinct natural history and is classified by the World Health Organization (WHO) as an independent entity, occurring with unique clinical and molecular features. The presence of a long preleukemic, myelodysplastic phase, called transient abnormal myelopoiesis (TAM), precedes the initiation of ML-DS and is defined by unusual chromosomal findings. Individuals with constitutional trisomy 21 have a profound dosage imbalance in the hematopoiesis-governing genes located on chromosome 21 and thus are subject to impaired fetal as well as to neonatal erythro-megakaryopoiesis. Almost all neonates with DS develop quantitative and morphological hematological abnormalities, yet still only 5–10% of them present with one of the preleukemic or leukemic conditions of DS. The acquired mutations in the key hematopoietic transcription factor gene GATA1, found solely in cells trisomic for chromosome 21, are considered to be the essential step for the selective growth advantage of leukemic cells. While the majority of cases of TAM remain clinically 'silent' or undergo spontaneous remission, the remaining 20% to 30% of them progress into ML-DS until the age of 4 years. The hypersensitivity of ML-DS blasts to chemotherapeutic agents, including but not limited to cytarabine, and drugs' increased infectious and cardiac toxicity have necessitated the development of risk-adapted treatment protocols for children with ML-DS. Recent advances in cytogenetics and specific molecular mechanisms involved in the evolution of TAM and ML-DS are reviewed here, as well as their integration in the improvement of risk stratification and targeted management of ML-DS. [ABSTRACT FROM AUTHOR]

Introduction: Transient abnormal myelopoiesis (TAM) is a transient, clonal myeloproliferative disorder unique to Down Syndrome (DS) babies. It is characterized by increased peripheral blasts and presence of GATA1 mutation. The clinical spectrum ranges from jaundice and hepatosplenomegaly to multi-organ failure and death. Here we present a case of a premature baby with DS diagnosed to have TAM with extramedullary involvement at birth who had a fatal outcome. Case report: A 30.3-week-old female fetus with DS had leukocytosis (WBC: 187.82 K/uL) with neutrophilia (ANC 27.65 K/uL), macrocytic anemia (RBC: 2.41 m/uL, Hb 8.8 g/dL, MCV 108.3, MCH 36.5, MCHC 33.7) and thrombocytosis (platelet count 361 K/uL) at birth. Liver panels demonstrated normal bilirubin levels with elevated liver enzymes (AST = 239 U/L, ALT = 216 U/L). Results: Peripheral smear showed marked leukocytosis with increased blasts (70%), nucleated RBCs, giant platelets, and megakaryocytic elements. Flow cytometry demonstrated two populations of cells: 20% myeloblasts and 26% dim CD45 CD34- cells. GATA1 mutation was present. Based on these findings a diagnosis of TAM with extramedullary hematopoiesis was made. She received two cycles of cytarabine chemotherapy. Though her WBC levels reached a low of 18.93 K/uL, she developed multi-organ failure, eventually leading to death on day 45. Discussion: TAM is a transient condition resulting in disease resolution in around 80% of cases. Death is reported in 10% of cases. Risk factors associated with early death include prematurity, hyperleukocytosis, elevated bilirubin levels. Management of high-risk babies with chemotherapy is recommended to improve survival.

Myeloid leukemia associated with Down syndrome (ML-DS) has a unique molecular landscape that differs from other subtypes of acute myeloid leukemia. ML-DS is often preceded by a myeloproliferative neoplastic condition called transient abnormal myelopoiesis (TAM) that disrupts megakaryocytic and erythroid differentiation. Over the last two decades, many genetic and epigenetic changes in TAM and ML-DS have been elucidated. These include overexpression of molecules and micro-RNAs located on chromosome 21, GATA1 mutations, and a range of other somatic mutations and chromosomal alterations. In this review, we summarize molecular changes reported in TAM and ML-DS and provide a comprehensive discussion of these findings. Recent advances in the development of CRISPR/Cas9-modified induced pluripotent stem cell-based disease models are also highlighted. However, despite significant progress in this area, we still do not fully understand the pathogenesis of ML-DS, and there are no targeted therapies. Initial diagnosis of ML-DS has a favorable prognosis, but refractory and relapsed disease can be difficult to treat; therapeutic options are limited in Down syndrome children by their stronger sensitivity to the toxic effects of chemotherapy. Because of the rarity of TAM and ML-DS, large-scale multicenter studies would be helpful to advance molecular characterization of these diseases at different stages of development and progression. [ABSTRACT FROM AUTHOR]

Simple Summary: Around 30% of children with Down Syndrome (DS) will develop Transient Abnormal Myelopoiesis (TAM) and 20% of them will progress to Acute Myeloid Leukemia (AML), mostly Megakaryoblastic Leukemia (AMKL). The optimal balance between treatment intensity and treatment-related toxicity has not yet been defined; neither the prognostic factors that determine the risk of developing AML nor the outcome. The aims of our retrospective study were to analyze the demographic/biological features of this population, identify possible risk factors and the optimal treatment. We observed that early intervention in TAM is effective to prevent a dismal outcome. The strongest poor-prognostic factor of DS-AML was sporadic DS-AML (non-AMKL immunophenotype), as well as complex karyotype and young age. Classical Myeloid Leukemia associated with DS (ML-DS) good outcome is mainly related to their low relapse rate. Even though the augmented sensitivity to chemotherapy seen in DS patients must be kept in mind, our data do not support the omission of high doses of cytarabine in ML-DS. Children with Down syndrome (DS) are at an increased risk of developing clonal myeloproliferative disorders. The balance between treatment intensity and treatment-related toxicity has not yet been defined. We analyzed this population to identify risk factors and optimal treatment. This single-center retrospective study included 78 DS patients <16 years-old with Transient Abnormal Myelopoiesis (TAM, n = 25), Acute Myeloblastic Leukemia (DS-AML, n = 41) of which 35 had classical Myeloid Leukemia associated with DS (ML-DS) with megakaryoblastic immunophenotype (AMKL) and 6 sporadic DS-AML (non-AMKL). Patients with DS-AML were treated according to four BFM-based protocols. Classical ML-DS vs. non-DS-AMKL were compared and the outcome of ML-DS was analyzed according to treatment intensity. Only four patients with TAM required cytoreduction with a 5-year Event-Free Survival probability (EFSp) of 74.4 (±9.1)%. DS-AML treatment-related deaths were due to infections, with a 5-year EFSp of 60.6 (±8.2)%. Megakaryoblastic immunophenotype was the strongest good-prognostic factor in univariate and multivariate analysis (p = 0.000). When compared ML-DS with non-DS-AMKL, a better outcome was associated with a lower relapse rate (p = 0.0002). Analysis of administered treatment was done on 32/33 ML-DS patients who achieved CR according to receiving or not high-dose ARA-C block (HDARA-C), and no difference in 5-year EFSp was observed (p = 0.172). TAM rarely required treatment and when severe manifestations occurred, early intervention was effective. DS-AML good outcome was associated with AMKL with a low relapse-rate. Even if treatment-related mortality is still high, our data do not support the omission of HDARA-C in ML-DS since we observed a trend to detect a higher relapse rate in the arm without HDARA-C. [ABSTRACT FROM AUTHOR]

Down syndrome (DS) is a congenital chromosomal abnormality caused by the presence of all or part of a third copy of chromosome 21 (+21). DS is frequently complicated by congenital heart or digestive tract diseases at birth. DS patients are prone to infections and have mental retardation, with dementia such as Alzheimer's disease showing in later life. Furthermore, malignancies with specific characteristics are also highly reported in DS patients compared with non-DS patients. Therefore, DS is believed to be a cancer predisposition syndrome due to the chromosomal instability. Acute myeloid leukemia (AML) and especially acute megakaryoblastic leukemia (AMKL) by French-American-British (FAB) classification are the most frequent hematological malignancies in DS patients, occurring at a rate that is 500 times higher than that in non-DS patients. Interestingly, transient abnormal myelopoiesis (TAM) is observed in approximately 10% of DS neonates with GATA1 mutations, and most TAM patients are asymptomatic and show spontaneous regression; however, about 10%–20% of TAM cases are fatal because of complications such as fetal effusion, liver fibrosis, and other complications.Acute lymphoblastic leukemia (ALL) is also associated with DS, occurring at a rate that is 20 times higher than that in non-DS patients. Furthermore, the prognosis of DS-ALL patients is poorer than that of non-DS-ALL patients. A recent genetic analysis revealed that more than half of DS-ALL cases have a mutation in the CRLF2–JAK pathway, indicating that JAK inhibitors might have a limited effect for DS-ALL patients.Notably, solid tumors such as neuroblastoma, Wilms tumor, and brain tumor, which are frequently observed in non-DS children, are rarely reported in DS children. The reason remains unknown, but it may be because of the triplication of the Down syndrome critical region 1 (DSCR1) gene on chromosome 21. In adult patients with DS, the expected age-adjusted incidence rates of solid tumors are low compared with age-matched euploid cohorts for most cancers except for testicular cancer. Although the average life expectancy of patients with DS will increase with advances in healthcare, the detailed health problems including cancer rates in older DS patients remain unknown. Therefore, these issues will be needed to be addressed in future studies.

Transient abnormal myelopoiesis (TAM) in neonates with Down syndrome is a distinct form of leukemia or preleukemia that mirrors the hematological features of acute megakaryoblastic leukemia. However, it typically resolves spontaneously in the early stages. TAM originates from fetal liver (FL) hematopoietic precursor cells and emerges due to somatic mutations in GATA1 in utero. In TAM, progenitor cells proliferate and differentiate into mature megakaryocytes and granulocytes. This process occurs both in vitro , aided by hematopoietic growth factors (HGFs) produced in the FL, and in vivo , particularly in specific anatomical sites like the FL and blood vessels. The FL's hematopoietic microenvironment plays a crucial role in TAM's pathogenesis and may contribute to its spontaneous regression. This review presents an overview of current knowledge regarding the unique features of TAM in relation to the FL hematopoietic microenvironment, focusing on the functions of HGFs and the pathological features of TAM. [Display omitted] • Transient abnormal myelopoiesis (TAM) in Down syndrome represents a unique self-regressing leukemia or preleukemia. • TAM emerges in the fetal liver (FL) by acquiring GATA1 mutations in the context of congenital trisomy 21. • TAM progenitor cells proliferate and differentiate into mature megakaryocytes and granulocytes. • This process occurs aided by hematopoietic growth factors produced in the FL. • The FL's microenvironment plays a crucial role in TAM's pathogenesis and may also contribute to its spontaneous remission. [ABSTRACT FROM AUTHOR]

Simple Summary: Acute megakaryoblastic leukemia (AMKL) is a rare and heterogeneous subtype of acute myeloid leukemia (AML). We show that such patients can be identified by flowcytometric immunophenotyping using the standardized EuroFlow panel. AMKL patients show a unique immunophenotypic profile, and among AMKL patients, various subgroups can be distinguished. Acute megakaryoblastic leukemia (AMKL) is a rare and heterogeneous subtype of acute myeloid leukemia (AML). We evaluated the immunophenotypic profile of 72 AMKL and 114 non-AMKL AML patients using the EuroFlow AML panel. Univariate and multivariate/multidimensional analyses were performed to identify most relevant markers contributing to the diagnosis of AMKL. AMKL patients were subdivided into transient abnormal myelopoiesis (TAM), myeloid leukemia associated with Down syndrome (ML-DS), AML—not otherwise specified with megakaryocytic differentiation (NOS-AMKL), and AMKL—other patients (AML patients with other WHO classification but with flowcytometric features of megakaryocytic differentiation). Flowcytometric analysis showed good discrimination between AMKL and non-AMKL patients based on differential expression of, in particular, CD42a.CD61, CD41, CD42b, HLADR, CD15 and CD13. Combining CD42a.CD61 (positive) and CD13 (negative) resulted in a sensitivity of 71% and a specificity of 99%. Within AMKL patients, TAM and ML-DS patients showed higher frequencies of immature CD34+/CD117+ leukemic cells as compared to NOS-AMKL and AMKL-Other patients. In addition, ML-DS patients showed a significantly higher expression of CD33, CD11b, CD38 and CD7 as compared to the other three subgroups, allowing for good distinction of these patients. Overall, our data show that the EuroFlow AML panel allows for straightforward diagnosis of AMKL and that ML-DS is associated with a unique immunophenotypic profile. [ABSTRACT FROM AUTHOR]

Children with Down syndrome (DS) are at increased risk of developing haematological malignancies, in particular acute megakaryoblastic leukaemia and acute lymphoblastic leukaemia. The microenvironment established by abnormal haematopoiesis driven by trisomy 21 is compounded by additional genetic and epigenetic changes that can drive leukaemogenesis in patients with DS. GATA-binding protein 1 ( GATA1 ) somatic mutations are implicated in the development of transient abnormal myelopoiesis and the progression to myeloid leukaemia of DS (ML-DS) and provide a model of the multi-step process of leukaemogenesis in DS. This review summarises key genetic drivers for the development of leukaemia in patients with DS, the biology and treatment of ML-DS and DS-associated acute lymphoblastic leukaemia, late effects of treatments for DS-leukaemias and the focus for future targeted therapy., Competing Interests: The authors declare that there is no conflict of interest., (© The Author(s), 2024.)

Abstract Pericardial effusion associated with transient abnormal myelopoiesis in Down's syndrome neonates needs to be diagnosed in a timely manner, and the comorbidities must be treated to prevent mortality. To our knowledge, the occurrence of basophilic/eosinophilic pericardial effusion without an increase of these cells in the peripheral blood and with no evidence of associated hypothyroidism is rare.

Transient abnormal myelopoiesis (TAM) is a unique entity that usually occurs in children with Down syndrome (DS) or with trisomy 21 mosaicism. The somatic GATA1 mutation is a distinct feature of TAM. At presentation, TAM can resemble congenital leukemia (CL), which unlike TAM has an extremely poor prognosis and requires prompt therapeutic interventions. Therefore, correct and timely distinction between the two entities is crucial. We report a case of a phenotypically normal infant diagnosed with CL during the first weeks of life that retrospectively was reassessed as TAM. No acute myeloid leukemia (AML) specific mutations were found except for trisomy 21 confined exclusively to leukemic blasts. Retrospectively GATA1 mutation was also detected in malignant cells, but somatic genome appeared to be intact.

Transient abnormal myelopoiesis (TAM) is a rare and unique disorder affecting Down syndrome (DS) newborns. This case series presents 5 cases of Down syndrome with TAM diagnosed during 2007–2015 with detailed analysis of immunophenotypic data of each case. CD34, CD13, CD33, CD117, CD41, CD61, CD7 and HLA-DR are useful markers for characterization of blasts of TAM.

Pericardial effusion associated with transient abnormal myelopoiesis in Down's syndrome neonates needs to be diagnosed in a timely manner, and the comorbidities must be treated to prevent mortality. To our knowledge, the occurrence of basophilic/eosinophilic pericardial effusion without an increase of these cells in the peripheral blood and with no evidence of associated hypothyroidism is rare. [ABSTRACT FROM AUTHOR]

A 38-year-old primiparous mother (gravida 1, para 0) at 27 weeks and 6 days' gestation reported that fetal movements had been absent for 6 days. All serological markers for infection were negative. Chorionic villus sampling at stillbirth delivery revealed trisomy 21 (47, XX, +21), indicative of Down syndrome. The macerated baby was female and weighed 1,290 g. There was no evidence of hydrops fetalis. Proliferating blast cells expressing megakaryoblastic/megakaryocytic antigen CD61 were mainly seen within the vessels, and some cells infiltrated outside of the vessels in almost all organs. Vessels of the umbilical cord and chorionic villi were filled with proliferating blast cells, but the blast cells were not apparent in the bone marrow. The diagnosis of transient abnormal myelopoiesis in Down syndrome was made. Hepatomegaly (64.5 g) was due to congestion and infiltration of CD61-positive blast cells within the vascular lumina and expanding outside the lumina accompanied by fibrotic change. The cause of death was attributed to liver insufficiency caused by liver fibrosis. An umbilical cord and chorionic villi examination may be helpful in the diagnosis of transient abnormal myelopoiesis when post-mortem examination is not permitted.

Transient abnormal myelopoiesis (TAM) also known as transient myeloproliferative disorder (TMD), a unique transient neonatal preleukaemic disorder characterized by clonal proliferation of megakaryoblasts, has been usually described to be associated with Down syndrome neonates. However, there are case reports of it occurring in neonates without Down phenotype, who are either mosaic for trisomy 21 or have trisomy 21 restricted to leukemic clone. This case report presents a case of TAM in a phenotypically normal neonate who presented in respiratory distress with features of tumour lysis syndrome (TLS) immediately after birth who was treated symptomatically and had spontaneous remission within three months. [ABSTRACT FROM AUTHOR]

Infants with Down Syndrome (DS) are at risk of developing a transient abnormal myelopoiesis (TAM). TAM is characterised by increased circulating blast cells but usually self-limiting. DS patients with TAM sometimes show fetal hydrops and effusion in body cavities, but the mechanism remains unclear. We report here a case of infant with DS who had pericardial effusion, TAM, and eosinophilia. In her pericardial effusion, white blood cell count was 6.0 × 103 /μ L, 41% of which were eosinophils. After administration of prednisolone, pericardial effusion gradually decreased, and TAM and eosinophilia improved. In order to elucidate the immunological mechanism, we measured the levels of 17 cytokines in her pericardial effusion fluid and serum. In her pericardial fluid, there were high levels of 12 cytokines, and they were higher than those in her serum. In particular, IL-6 (44,573 pg/mL), IL-8 (4,865 pg/mL), and IL-13 (579.41 pg/mL) were at extremely high levels in her pericardial fluid. After administration of prednisolone, the levels of 8 of the 12 elevated cytokines in her pericardial fluid decreased and all of the elevated cytokines decreased in her serum. Corticosteroids can be effective to reduce cytokine levels and the amount of effusion in patients with DS. It is presumed that effusion seen in DS with TAM could be related to an abnormal production of cytokines at the effusion site. [ABSTRACT FROM AUTHOR]

Congenital leukemia is rare disease with an incidence of one to five cases per million births. Transient abnormal myelopoiesis (TAM), also called transient myeloproliferative disorder, is a pre-leukemia disorder that may occur in Down syndrome (DS) or non-DS infants. TAM may enter spontaneous remission; however, continual monitoring is required, as this disorder has been observed to develop into acute megakaryoblastic leukemia in 16-30% of cases. In the literature, 16 cases of TAM in non-DS infants have been reported. The case presented in the current study is, to the best of our knowledge, the first case of an Italian non-DS newborn presenting with clinical manifestations of acute leukemia at five days after birth, exhibiting a normal karyotype, trisomy 21 only in blast cells, and spontaneous remission. Chromosomal analyses on peripheral blood cells, bone marrow cells and dermal fibroblasts were conducted using a G-banding technique, and fluorescence in situ hybridization (FISH) was used to identify the critical regions of DS. Amplification of GATA binding protein 1 (GATA1) exon 2 genomic DNA was performed using polymerase chain reaction. Cytogenetic analysis of 50 peripheral blood cells and dermal fibroblasts from the patient revealed a normal karyotype: 46, XX. Conversely, cytogenetic analysis of the patient's bone marrow revealed an abnormal karyotype 47, XX+21. In order to investigate this result, FISH was performed, which identified the presence of three signals in 70% of the cells and two signals in 30% of bone marrow cells. GATA1 sequencing revealed the substitution of a single base (c.150delG) in exon 2. Seven months after the initial analysis, FISH and cytogenetic analyses of the stimulated/unstimulated peripheral blood cells and bone marrow cells were performed, revealing that each exhibited diploid signals, as observed in a normal karyotype. [ABSTRACT FROM AUTHOR]

Infants with Down syndrome (DS) are at risk of developing a transient myeloproliferative disorder during the neonatal period, known as transient abnormal myelopoiesis (TAM). It is characterized by clonal myeloproliferation and is typically self-limiting. However, TAM can be a life-threatening disorder, when complicated by liver fibrosis. Here, we evaluated cytokine profiles in two male DS infants having TAM with or without liver dysfunction. The first patient, Patient 1, had hyperleukocytosis with cholestatic liver dysfunction, coagulopathy, and increased counts of blasts and was treated with exchange transfusion (ExT) due to the serious general condition. In Patient 1, serum interleukin (IL)-8 and plasma transforming growth factor (TGF)-β 1 levels were markedly elevated before ExT (1,518.2 pg/mL and 17,635 pg/mL, respectively). After ExT, serum IL-8 and plasma TGF-β 1 levels decreased to 40.7 pg/mL and 6,847 pg/mL, respectively. However, Patient 1 died on day 56 due to cholestatic liver dysfunction; namely, this patient represents fatal TAM. The second patient, Patient 2, had hyperleukocytosis with increased counts of blasts without liver dysfunction and was treated with cytarabine. In Patient 2, plasma TGF-β 1 levels, but not plasma IL-8, were elevated (9,068 pg/mL and 28 pg/mL, respectively). Patient 2 was discharged on day 47. In summary, plasma TGF-β 1 levels were elevated in the two DS infants with TAM, regardless of the presence or absence of hepatic fibrosis. Importantly, fatal TAM is assoicated with the elevated serum level of IL-8. We thus propose that IL-8 may be involved in the pathogenesis of liver fibrosis. [ABSTRACT FROM AUTHOR]

A 38-year-old primiparous mother (gravida1, para 0) at 27 weeks and 6 days' gestation reported that fetal movements had been absent for 6 days. All serological markers for infection were negative. Chorionic villus sampling at stillbirth delivery revealed trisomy 21 (47, XX, +21), indicative of Down syndrome. The macerated baby was female and weighed 1,290 g. There was no evidence of hydrops fetalis. Proliferating blast cells expressing megakaryoblastic/megakaryocytic antigen CD61 were mainly seen within the vessels, and some cells infiltrated outside of the vessels in almost all organs. Vessels of the umbilical cord and chorionic villi were filled with proliferating blast cells, but the blast cells were not apparent in the bone marrow. The diagnosis of transient abnormal myelopoiesis in Down syndrome was made. Hepatomegaly (64.5 g) was due to congestion and infiltration of CD61-positive blast cells within the vascular lumina and expanding outside the lumina accompanied by fibrotic change. The cause of death was attributed to liver insufficiency caused by liver fibrosis. An umbilical cord and chorionic villi examination may be helpful in the diagnosis of transient abnormal myelopoiesis when post-mortem examination is not permitted. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Myeloid leukemia associated with Down syndrome (ML-DS) has a unique molecular landscape that differs from other subtypes of acute myeloid leukemia. ML-DS is often preceded by a myeloproliferative neoplastic condition called transient abnormal myelopoiesis (TAM) that disrupts megakaryocytic and erythroid differentiation. Over the last two decades, many genetic and epigenetic changes in TAM and ML-DS have been elucidated. These include overexpression of molecules and micro-RNAs located on chromosome 21, GATA1 mutations, and a range of other somatic mutations and chromosomal alterations. In this review, we summarize molecular changes reported in TAM and ML-DS and provide a comprehensive discussion of these findings. Recent advances in the development of CRISPR/Cas9-modified induced pluripotent stem cell-based disease models are also highlighted. However, despite significant progress in this area, we still do not fully understand the pathogenesis of ML-DS, and there are no targeted therapies. Initial diagnosis of ML-DS has a favorable prognosis, but refractory and relapsed disease can be difficult to treat; therapeutic options are limited in Down syndrome children by their stronger sensitivity to the toxic effects of chemotherapy. Because of the rarity of TAM and ML-DS, large-scale multi-center studies would be helpful to advance molecular characterization of these diseases at different stages of development and progression., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Li and Kalev-Zylinska.)

Down syndrome (DS) is a common genetic disorder and is associated with an increased likelihood of many diseases, including defects of the heart, genitourinary system, gastrointestinal tract, and oncological diseases. The aim of this study was to analyze medical problems occurring in newborns with DS and to create a basic diagnostic and therapeutic algorithm intended primarily for neonatologists, pediatricians, family physicians, and physicians of other specialties caring for children with DS. Over a 5-year period, the medical records of 161 neonates with Down syndrome from four neonatology departments in Poznan, Poland, were examined. After applying exclusion criteria, 111 patients were analyzed. Data obtained from medical history included sex, week of gestation, birth weight, APGAR score, clinical symptoms, peripheral blood count with smear, and clinical features such as jaundice, hemorrhagic diathesis, ascites, hepato- or splenomegaly, pericardial or pleural effusion, respiratory failure, and other rare transient signs of abnormal myelopoiesis: fetal edema, hepatic fibrosis, renal failure, and rush. In the study group, 8% of children with Down syndrome were diagnosed with a heart and 1.8% with a genitourinary defect. Transient abnormal myelopoiesis syndrome (Transient abnormal myelopoiesis (TAM)) was found in 10% of newborns with DS. A blood count with blood smear, cardiology consultation with echocardiography, and an abdominal ultrasound should be performed in the first few days after birth in all newborns with Down syndrome. If this is not possible and the child's condition is stable, these tests can be performed within 2-3 months after birth.

Transient leukemia (TL) also referred to as transient abnormal myelopoiesis (TAM) or transient myeloproliferative disorder (TMD) is a unique syndrome that frequently occurs in newborns with Down syndrome (DS). It manifests in the first few days of life and shows leukocytosis with blast cells in the blood and bone marrow. This leukemia resolves spontaneously within first few months of life in the majority of cases. In this report we describe two newborns with a karyotype of 47,XY,+21, presented with marked leukocytosis and many blast cells in the peripheral blood. In both the cases, the blasts disappeared and the total leukocyte count reverted to normal without any specific treatment. [ABSTRACT FROM AUTHOR]