Intrauterine diagnosis and management of transient myeloproliferative disorder

Molecular Mechanisms of the Genetic Predisposition to Acute Megakaryoblastic Leukemia in Infants With Down Syndrome

Individuals with Down syndrome are genetically predisposed to developing acute megakaryoblastic leukemia. This myeloid leukemia associated with Down syndrome (ML–DS) demonstrates a model of step-wise leukemogenesis with perturbed hematopoiesis already presenting in utero, facilitating the acquisition of additional driver mutations such as truncating GATA1 variants, which are pathognomonic to the disease. Consequently, the affected individuals suffer from a transient abnormal myelopoiesis (TAM)—a pre-leukemic state preceding the progression to ML–DS. In our review, we focus on the molecular mechanisms of the different steps of clonal evolution in Down syndrome leukemogenesis, and aim to provide a comprehensive view on the complex interplay between gene dosage imbalances, GATA1 mutations and somatic mutations affecting JAK-STAT signaling, the cohesin complex and epigenetic regulators.

Recent advances in the understanding of transient abnormal myelopoiesis in Down syndrome

Neonates with Down syndrome (DS) have a propensity to develop the unique myeloproliferative disorder, transient abnormal myelopoiesis (TAM). TAM usually resolves spontaneously in ≤3 months, but approximately 10% of patients with TAM die from hepatic or multi-organ failure. After remission, 20% of patients with TAM develop acute myeloid leukemia associated with Down syndrome (ML-DS). Blasts in both TAM and ML-DS have trisomy 21 and GATA binding protein 1 (GATA1) mutations. Recent studies have shown that infants with DS and no clinical signs of TAM or increases in peripheral blood blasts can have minor clones carrying GATA1 mutations, referred to as silent TAM. Low-dose cytarabine can improve the outcomes of patients with TAM and high white blood cell count. A number of studies using fetal liver cells, mouse models, or induced pluripotent stem cells have elucidated the roles of trisomy 21 and GATA1 mutations in the development of TAM. Next-generation sequencing of TAM and ML-DS patient samples identified additional mutations in genes involved in epigenetic regulation. Xenograft models of TAM demonstrate the genetic heterogeneity of TAM blasts and mimic the process of clonal selection and expansion of TAM clones that leads to ML-DS. DNA methylation analysis suggests that epigenetic dysregulation may be involved in the progression from TAM to ML-DS. Unraveling the mechanisms underlying leukemogenesis and identification of factors that predict progression to leukemia could assist in development of strategies to prevent progression to ML-DS. Investigation of TAM, a unique pre-leukemic condition, will continue to strongly influence basic and clinical research into the development of hematological malignancies.

Fetal/Neonatal Pericardial Effusion in Down's Syndrome: Case Report and Review of Literature

We report a preterm (35 ^4/7 weeks) male neonate with Down's syndrome (DS) diagnosed with isolated pericardial effusion (PE) at 20 weeks of gestation. He was born by precipitous delivery, needed no resuscitation and presented within first 24 hours of life with respiratory distress, anemia due to feto-maternal bleed, hypotension, hepatomegaly, and coagulopathy. Postnatal echocardiography confirmed a 5 mm rim of PE without tamponade, normal cardiac structure, and function. He was stabilized with ventilation, packed red cell, fresh frozen plasma, inotropes (dopamine, dobutamine, and adrenaline), and steroid (hydrocortisone). Subsequent evaluation confirmed hypothyroidism, transient myeloproliferative disorder (TMD), hepatic failure due to fibrosis/cirrhosis with portal hypertension, and steroid sensitive hypotension on two occasions possibly due to adrenal insufficiency. PE completely resolved over 2 weeks. In view of progressively worsening liver failure with ascites and portal hypertension, the family opted for palliation. Literature review has been discussed regarding perinatal onset of PE in DS.

Prenatal therapy in transient abnormal myelopoiesis: a systematic review

OBJECTIVE

To systematically review current evidence regarding prenatal diagnosis and management of transient abnormal myelopoiesis (TAM) in fetuses with trisomy 21. A novel case of GATA1-positive TAM, in which following serial in utero blood transfusion clinical improvement and postnatal remission were observed, is included.

SEARCH STRATEGY AND DATA COLLECTION

A systematic search of electronic databases (inception to October 2014) and reference lists, hand-searching of journals and expert contact. All confirmed cases of prenatal TAM were included for analysis. Data on study characteristics, design and quality were obtained.

RESULTS

Of 73 potentially relevant citations identified, 22 studies were included, describing 39 fetuses. All studies included comprised single case or small cohort studies; overall quality was 'very low'. Fetal/neonatal outcome was poor; 12 stillbirths (30.8%), 4 neonatal deaths (10.2%) and 7 infant deaths (17.9%). In two cases, the pregnancy was terminated (5.1%). TAM was primarily detected in the third trimester (79.4%), and in 14 a retrospective diagnosis was made postpartum. Ultrasound features indicative of TAM included hepatomegaly±splenomegaly (79.5%), hydrops fetalis (30.8%), pericardial effusion (23.1%) and aberrant liquor volume (15.4%). When performed, liver function tests were abnormal in 91.6% of cases.

CONCLUSIONS

Prenatal TAM presents a challenging diagnosis, and prognosis is poor, with consistently high mortality. A low threshold to measure haematological and biochemical markers is advised when clinical features typical of TAM are detected in the context of trisomy 21. Larger prospective studies are warranted to accurately ascertain the role of GATA1 analysis and potential value of prenatal therapy.

A dysmorphic newborn with petechiae and a 'Big Heart'

A male fetus was noted to have an isolated pericardial effusion. At birth, he had dysmorphic features of Down syndrome and extensive petechiae. He was diagnosed to have transient myeloproliferative disorder. The large pericardial effusion and TMD spontaneously resolved. At 4 years of age, he was diagnosed with acute megakaryoblastic leukaemia, underwent chemotherapy and achieved complete remission.

Managing the difficult case of fetal anemia

OBJECTIVES

To describe a series of complex fetal anemia cases, detail the appropriate investigations and management, and review the literature.

METHODS

Four cases of non-red cell alloimmunization or infective cases of fetal anemia are presented.

RESULTS

Of the four cases presented, one was a neonatal death, one pregnancy was terminated, one case was diagnosed with Diamond Blackfan anemia, and one case was due to recurrent feto-maternal hemorrhages despite negative Kleihauer tests.

CONCLUSIONS

Non-alloimmune causes of fetal anemia can be difficult to manage. Some cases require repeated and frequent intrauterine transfusions. The perinatal mortality and preterm delivery rates are increased, and some cases require considerable long-term treatment including regular transfusions. We present our experience of a series of non-immune fetal anemia managed in a tertiary unit, review the literature, and suggest appropriate management.

Myeloid proliferation without GATA1 mutations in a fetus with Down syndrome presenting in utero as a pericardial effusion

An isolated pericardial effusion was observed during a routine prenatal ultrasound in a fetus of 30 and 3/7 weeks gestation. Amniocentesis was performed and revealed a trisomy 21. After prenatal counseling, the parents opted for termination of the pregnancy at 32 weeks. Postmortem examination confirmed the presence of a pericardial effusion, without structural cardiac anomalies, and showed the development of ascites and subcutaneous edema. Histological examination showed an infiltrate of megakaryoblasts and irregular, dysplastic megakaryocytes confined to the epicardium, the pericardial lymph nodes, and the pancreas, consistent with a myeloid proliferation related to Down syndrome. Sequencing of exons 2 and 3 of the GATA1 gene from the umbilical cord blood and from megakaryoblast infiltrate showed no mutation. A high incidence of chromosomal abnormalities, in particular trisomy 21, has been described in fetuses with pericardial effusion. However, myeloid proliferation related to Down syndrome without GATA1 mutations is extremely rare. To our knowledge, only one such case has been reported to date. We present here a 2nd case, which further supports the hypothesis that hyperproliferation of megakaryocytes in a subset of Down syndrome patients may be initiated by events other than GATA1 mutations.

Transient myeloproliferative disorder and eosinophilic pericardial effusion in a down syndrome neonate

Transient myeloproliferative disorder seen in neonates with Down syndrome is often thought to have a benign course. The authors describe the clinical and laboratory profile of a neonate with Down phenotype and transient myeloproliferative disorder with pericardial effusion as co-morbidity. Pericardial fluid analysis showed eosinophils. Pericardial effusion resolved with prednisolone therapy. Regression in hepatosplenomegaly with clearance of blasts was seen by third week of illness. The clinical course suggested a benign infiltration of the pericardium. Presence of eosinophils supports the differentiating capability of the blast cells in transient myeloproliferative disorders.

Four cases of fetal hypoechoic hepatomegaly associated with Trisomy 21 and transient abnormal myelopoiesis

OBJECTIVE

Our objective was to determine the clinical significance of fetal hypoechoic hepatomegaly and serial change of liver sizes.

METHODS

The liver sizes of four fetuses with hypoechoic hepatomegaly were serially estimated by liver length, as measured from the dome of the right hemidiaphragm to the tip of the right lobe.

RESULTS

All cases were associated with trisomy 21 or transient abnormal myelopoiesis (TAM). Two cases were trisomy 21 with TAM, one case was a phenotypically normal newborn, who had developed TAM during the fetal period, and the last case was trisomy 21 without TAM. In the last case, it is speculated that TAM had developed and regressed completely before birth. Two cases, whose hepatomegaly had improved before birth, showed good prognosis and the other two cases, in whom improvement had not been observed, resulted in death after birth by liver failure.

CONCLUSION

These experiences show that one of the differential diagnoses of hypoechoic hepatosplenomegaly is TAM and that the change of live size is a predictor of prognosis.

Isolated pericardial effusion in the human fetus: a report of three cases

OBJECTIVE

Our objective was to determine the possible underlying etiologies and outcome in isolated fetal pericardial effusion.

METHODS

Doppler fetal echocardiography allowed the diagnosis of pericardial effusion in three patients and revealed the etiology in two.

RESULTS

We present the findings in three cases of isolated pericardial effusion. In the first, the pericardial effusion was a manifestation of trisomy 21 associated with a myeloproliferative disorder. In the second, the pericardial fluid collection was the first sign of an autosomal recessive disease, idiopathic infantile arterial calcification. The third case was remarkable because of the spontaneous resolution of a large pericardial fluid collection.

CONCLUSION

Isolated fetal pericardial effusion covers a wide spectrum of etiologies from severe genetic and chromosomal diseases to transient forms.

Fetal hydrops and hepatosplenomegaly in the second half of pregnancy: a sign of myeloproliferative disorder in fetuses with trisomy 21

OBJECTIVE

To demonstrate the relationship between fetal hydrops and/or hepatosplenomegaly in the second half of pregnancy with a myeloproliferative disorder in fetuses with trisomy 21 or mosaic trisomy 21.

DESIGN

A retrospective case series.

SUBJECTS

Cases were selected from 79 cases of trisomy 21 diagnosed in our prenatal unit between 1993 and 1999.

METHODS

All fetuses had a detailed sonographic anatomic survey and biometry. Doppler of the umbilical and middle cerebral arteries, ductus venosus, inferior vena cava and umbilical vein was performed whenever possible. Two-dimensional echocardiography supplemented by color Doppler flow mapping and spectral pulsed wave Doppler was performed in all cases of fetal hydrops. Fetal karyotyping was obtained by amniocentesis, chorionic villus sampling or fetal blood sampling. In the presence of fetal hydrops a cordocentesis was performed for fetal hematology, biochemistry and TORCH serology. In cases with diagnosis of myeloproliferative disorder, peripheral blast cells were characterized by microscopy, cytochemistry and determination of surface markers. All cases with myeloproliferative disorder were stillborn and subsequently had a postmortem examination performed.

RESULTS

During the study period 79 cases of trisomy 21 were diagnosed. Eleven of these had fetal hydrops. Three of these fetuses presented with hepatosplenomegaly and myeloproliferative disorder in the second and third trimesters. In addition, one fetus with sonographic markers of trisomy 21, where karyotyping was unfortunately unsuccessful, presented with hepatosplenomegaly, hydrops and myeloproliferative disorder. In the four fetuses with hepatosplenomegaly and hydrops, serology was negative for congenital infection. The characteristics of blast cells in the peripheral blood smear revealed a myeloproliferative disorder.

CONCLUSION

Fetal hydrops and/or hepatosplenomegaly in the second half of pregnancy, although suggestive of infectious etiology, may be a sign of myeloproliferative disorder in fetuses with trisomy 21 or mosaic trisomy 21. There is a possibility that a transient myeloproliferative disorder is a more common cause of mid or late-trimester hydrops in cases of trisomy 21 than previously thought. In these hydropic fetuses the prognosis seems to be poor. On the other hand we can speculate that a myeloproliferative disorder and the associated hepatosplenomegaly and/or hydrops may show spontaneous remission or that the transient myeloproliferative disorder may be without any detectable ultrasonographic signs and therefore may be more frequent in utero than realized.

Isolated pericardial effusion and transient abnormal myelopoiesis in a fetus with Down's syndrome

Isolated pericardial effusion was detected in a fetus at 34 weeks of gestation. A male infant weighing 2,044 g was born by cesarean section because of a non-assuring fetal heart rate pattern at 35 weeks of gestation. Transient leukocytosis (36,100/microl) with 49% blast cells was seen in this neonate. The infant's karyotype was 47, XY + 21. The pericardial effusion disappeared after treatment with prednisolone at a dose of 2 mg/kg/day. Hypothyroidism was subsequently found. Thus, the subject patient with Down's syndrome developed isolated pericardial effusion, transient abnormal myelopoiesis (TAM), and hypothyroidism. Because more than 20% of the infants with TAM and Down's syndrome develop acute nonlymphocytic leukemia in early childhood, he is being closely observed.

Hematologic disorders and nonimmune hydrops fetalis

Hematologic disorders are implicated in approximately 10% to 27% of cases of nonimmune hydrops fetalis. In almost all of these disorders, anemia leading to heart failure, edema, ascites, and anasarca is the final common denominator. The etiology of the anemia in these cases can be conveniently divided into two categories: (1) excessive erythrocyte loss by hemolysis or hemorrhage, and (2) erythrocyte underproduction. The former include intrinsic erythrocyte abnormalities such as alpha-thalassemia and glucose-6-phosphate dehydrogenase deficiency, and conditions with excessive fetal blood loss such as fetomaternal hemorrhage and twin-twin transfusion. The latter include bone marrow replacement syndromes and conditions associated with failure of erythrocyte production. The presentation, diagnosis, and management of hematologic disorders associated with nonimmune hydrops fetalis are reviewed.