Transient Myeloproliferative Disorder In Down Syndrome

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Transient Myeloproliferative Disorder In Down
Syndrome

• Washington University School Of Medicine
• St Louis Missouri
• Pediatric Hematology/Oncology
• Ghada Kunter MD
• 6/3/05

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Case Presentation

• Newborn baby girl with Down syndrome, WBC
  count of 47 with 40 blasts, hepatomegaly,
  ascitis, anemia and thrombocytopenia

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• What does this pt have?

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Case Presentation

• 38 wks baby girl was born by C/S to a
• 25 y-old G8, P6 mother with no known medical
  illness
• She had a pre-natal diagnosis of trisomy 21with
  nl 2D echo
• Baby was intubated immediately because of
  decrease respiratory efforts

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Case Presentation

• P/E
• Wt 3.54, HC 33.8, L 46.5
• Large baby, edmatous
• Macrocephalic
• Hypertelolism
• AF large and flat
• Low set ears

• Lungs course BS bilaterally
• CVS loud S2, SEM
• Abdomen distended, enlarged liver 6 cm, ascitis
• Ext edematous hands and feet
• CNS floppy baby

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First day lab tests

• WBC 47
• Hgb 8.5
• Plat 113
• MCV 123
• Blasts 34
• Segs 26
• ALT 158
• AST 61
• Alk Ph 166

• TB 4.7
• Direct 2.9
• Indirect 1.8
• LDH 4928
• Uric acid 7.7

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Peripheral Blood Smear

• Abundant blasts with high N/C ratio
• These cells are
• -pleomprphic
• -ranging in size between
• 7-20 Mm
• Fine chromatin, occasional prominent nucleolus,
  rare cytoplasmic vacuoles
• PB flow cytometry (ordered)

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Hospital Course

• CXR cardiomegaly ( 2D echo PFO, PDA)
• Abdominal US hepatomegaly, ascitis
• Peritoneal fluid blast
• PB flow cytometry suggestive of TMD, blasts are
  neg for NBE, positive for MPD
• Blasts cop-express CD34, CD117, CD7, CD41,
  CD61, glycophorine-A
• On day 3 she developed papular rash which
  involved the entire body with few pustules
• Skin biopsy suggestive of TMD

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Myeloproliferative Syndromes

• Clonal stem disorders resulting in excessive
  proliferation of one or more cell lineages

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Incidence of TMD in Trisomy 21

• Trisomy 21 is the most frequent human chromosomal
  abnormality
• The incidence in the general population is 1 in
  600-800 live births
• TMD occur in 10-20 of infants with DS( 30 will
  develop AMKL within the first 3 yrs)
• Children with DS have 20-folds higher incidence
  of leukemia than unaffected children
• most leukemias in DS is AMKL
• ( 500-fold higher than in healthy children),
  median age
• 2 ys

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Transient Myeloproliferative Disorder

• DS kids are uniquely predisposed to clonal
  disorders affecting MKC lineage (TMD, AMKL)
• The leukemic cells in TMD derived from a common
  erythroid and megakaryoblastic progenitor
• The cells express the transcription factor GATA1
• Harbor somatic mutations of the gene encoding
  GATA1

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Description of GATA-1

• Phosphorelated X-linked gene, encoded on the
  X-chromosome
• GATA-1 contains DNA binding and transactivation
  activity within 3 functional domains, 2 zink
  fingers (N,C), N-terminal activation domain
• C-finger is responsible for binding of GATA1 to
  typical GATA-binding sites
• N-finger, both binds DNA and recruiting a
  cofactor friend of GATA (FOG-1)
• Both primarily expressed in hematopoietic cells,
  essential for development of RBCs MKC
• FOG1 Binds to promoters/enhancers of countless
  genes expressed in RBCs MKC

J.D. Crispino/Seminars in cell develop biology
16 (2005) 137-147
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Function Of GATA1(FOG-1)

• GATA1 is an essential transcriptional regulator
  of MKC differentiation
• Required for the proper development of erythroid
  cells, eosinophils, mast cells and MKC
• Required in megakaryopoiesis
• proliferation, maturation and differentiation of
  MKC

FOG1 can stimulate or inhibit GATA1 activity
depending on cell and promoter GATA1 FOG1 complex
controls the expression of distinct sets of gene
in MKC and erythroid cells is not understood
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What Happen to GATA1 IN TMD?

• GATA1 is altered in 2 myeloproliferative
  conditions in DS
• TMD
• AMKL
• These pts harbor acquired mutations in the
  sequences encoding the N-terminal AD of GATA1
• Each of these mutations abolish the translation
  of full-length GATA1 but allows the expression of
  a shorter isoform named GATA1s
• GATA1s binds DNA normally and interacts with
  FOG-1 to the same extent
• The lack of the N-terminal AD has reduced
  transcriptional activity

Somatic mutations in GATA1 are seen in both TMD,
AMKL associated with DS
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Nature of GATA1 mutations

• Characterization of GATA1 mutations in DS All
  alterations are predicted to block the expression
  of full-length 50-KD isoform of GATA1 but not
  completely, instead leads to the production of a
  smaller GATA1 isoform called GATA1s which is
  40-KD which initiates at the methionine at aa 84,
  lacks the N-terminal transactivation domain,
  retains both zink-fingers that involve with DNA
  binding and the interaction with FOG-1
• Missense mutation in the N ZF that convert Valine
  to methionine (V205M), Valine 205 to Glycine,
  Glycine 208 Serine
• Insertion
• Deletion of small number of nucleotides lead to
  the introduction of premature stop codon in the
  sequences that code the N-terminal
  transcriptional activation domain
• Nonsense mutations introduce a premature stop
  codons within the first 83 aa
• Splice site mutations which interfers with the
  Ist coding exon in the GATA1 mRNA

Mutations in the N-terminal zink-finger of the
X-linked gene GATA1 has been associated with
variety of dyseryhtropoietic anemias and
thrombocytopenias
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Location of GATA-1 mutation

• Acquired mutations in exon 2 have been linked to
  patients with Down syndrome and TMD.
• Groet et al (2003) Lancet 10/10 patients
• Crispino (2003) Blood 6/6 patients
• Rainis (2003) Blood 16/17 patients
• Hitzler (2003) Blood 9/12 patients
• In pts with TMD who subsequently develop AMKL,
  the exon 2 mutations persist.
• Hitzler (2003) Blood
• Acquired mutations in exon 2 have also been
  linked to a set of identical twins with acquired
  Tr21 and AMKL.
• Rainis (2003) Blood
• Rainis et al. discovered a deletion of 2
  nucleotides within exon 2

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• Does TMD evolve into AMKL?
• What are the genetic events?
• Are all cases of AMKL preceded by TMD?

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Leukemogenic twist for GATA

• Human AML arising from the accumulation of
  mutations in the HSCs
• Trisomy 21 increase expression of a gene or
  genes on chromosome 21 which stimulate abnormal
  proliferation of HSCs with frequent induction of
  TMD
• In some cases the expanded pool of dividing cells
  acquires new mutations and lead to overt leukemia

nature genetics.vol32,9/02
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When Does The Mutation Happen?
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Missense mutations in the N-terminal zinc finger
of GATA1 result in abnormal hematopoiesis

• Disrupt FOG-1 interactions
• V205M leads to both severe macrothrombocytopenia
  and dyserythropoietic anemia
• D218G to macrothrombocytopenia and mild
  dyserythropoiesis without anemia
• G208S to macrothrombocytopenia
• Disrupt DNA binding
• R216Q leads to macrothrombocytopenia with
  ß-thalassemia.

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Mouse Models of GATA1Deficiency

• Knockout and chimera studies in mice have have
  established that GATA-1 null cells exhibit
  aberrant differentiation of both RBCs and
  megakaryocytes.
• Gata1 null mice die in utero of anemia.
• Gata1 null ES cells to do not contribute well to
  RBCs or megakaryocytes in chimeric mice.
• Gata1 null ES cells differentiated in vitro
  exhibit abnormal hematopoiesis.
• Fog1-/- mice also show compromised hematopoiesis.

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More On GATA1 Effect

• Mice with low level GATA-1 due to specific
  deletion of regulatory region or promoter
  sequences exhibit degree of anemia and
  thrombocytopenia,
• erythroid maturation is also adversely affected
• GATA-1 deficient MKC exhibit marked abnormal
  proliferation and expansion of immature MKC in
  mice
• Knock-down mice GATA-1 deficient ES cells failed
  to give rise to mature erythroid cell ( vitro,
  vivo)
• Acquired mutations in GATA-1 associated with AMKL
  in children with DS, also present in TMD blasts

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More studies

• Xu et al. showed overexpression of GATA1s did not
  evoke any changes in the growth properties of the
  leukemic cells
• Restoration of wild-type GATA-1 express in
  DS-AMKL cells might reverse the leukemia and lead
  to differentiation, it is very likely that loss
  of GATA1 directly contribute to leukemia

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Acquired mutations in GATA1 in AMKL of DS

• Crisprino/Ped Blood Cancer 0544-40-44

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Transient Myeloproliferative Disorder

• Several reports support that TMD is a disorder of
  fetal liver
• occur exclusively in DS
• TMD generally present either at birth or within
  the first 2 weeks of life or in stillborns
• TMD can develop in utero
• Self limited an acute leukemia-like disorder
• Undergoes spontaneous remission ( time when
  hematopoiesis switched to BM)
• Usually regress by spontaneously by age of 2-3 ms
• -Incidental finding
• -Underestimated
• -Undiagnosed
• Profound pancytopenias are rare
• Although TMD is transient, but it has many
  clinical, lab features malignancy

British Journal of hematology, 03,120,930-938
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Complications Of TMD

• Liver fibrosis which is life threatening and
  sometimes fatal,
• The frequency of liver fibrosis is not known
• Infants may die of fulminant liver failure
• Extensive myelofibrosis
• Generalized visceral fibrosis are occasionally
  present (pancreatic, cardiac fibrosis was noted)

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Liver Fibrosis

• In minority of pts withTMD, abnormal
  proliferation of blasts persist and sometimes may
  result in fatal fibrosis of several organs (esp
  the liver)
• hepatomegaly
• ascitis
• elevated liver Es
• Rarely, TMD itself is the direct cause of death (
  hepatic fibrosis)
• British Journal of hematology, 03,120,930-938

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Failure Of Transition

• Failure to make a timely transition to medullary
  hematopoiesis and production of cytokines such as
  platelets growth factor or transforming growth
  factor B by MKB may lead to overwhelming fibrosis
• The transition from hepatic to medullary
  myeloiposis accompanies the regression of TMD

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Skin Manifestation in TMD

• 36 wks NB male with DS and persistent
  leukocytosis 106 and 42 blasts, edema, HPM, RD,
  no anemia or thrombocytopenia,
• Day 13, WBC 157, generalized papular rash, skin
  biopsy TMD
• Week 6 WBC decreased and skin lesions resolved

• 31 wks NB female with DS and WBC 87 and 36
  blasts in the PB
• Crusted vesiculopastular lesions on the cheeks
  and chin
• On day 2 biopsy was obtained consistent with TMD,
  resolved on day 14

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Is it a true leukemia?

• Still controversial wheather TMD is true leukemia
  or nonneoplastic unstable hematopoiesis
• The blast in TMD are indistinguishable
• morphology
• surface markers
• The blasts in TMD are dysplastic megakaryoblasts
• Molecular analyses (strong evidence of neoplastic
  nature)
• the distinction between TMD and AKML remains
  unknown

• No definite conclusion!

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Management of TMD

• Supportive care
• If WBC counts exceed 200, exchange transfusion or
  leukopharesis may avoid complications of
  hyperleukocytosis
• In case of imminent death from liver fibrosis,
  therapy is indicated
• In rare cases of TMD where cytopenias or
  hyperleukocytosis is life threatening, cytotoxic
  therapy is considered
• Low dose Ara-C may be used as it is sometimes
  curative in AMKL in DS (either LD Ara-c or
  standard Rx for AMKL)

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Continue Hospital Course

• Pt was started on VLD Ara-C at 0.4mg/kg/dose Q12h
  X 7 days every other week up to total of 4 cycles
• Serial abdominal US ( resolution of ascitis)
• Pt was extubated DOL 30
• PO feed DOL 34

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Summary

• GATA1s is an oncogenic transcription factor that
  acts by blocking (terminal) differentiation in a
  subset of hematopoietic cells
• GATA1s binds DNA but does not trans-activate
• Expression of GATA1s part of a multistep process
  involved in leukemogenesis
• Acquired mutations in the GATA-1 gene have been
  reported in all individuals examined with DS-AMKL
  ,TMD