Dysfunctional Telomere Maintenance in the Pathogenesis of by dnm98994

VIEWS: 0 PAGES: 25

									 Dysfunctional Telomere Maintenance
       in the Pathogenesis of
  Myelodysplastic Syndromes (MDS)


             Monica Bessler, M.D., Ph.D.
Department of Internal Medicine, Division of Hematology
      Washington University School of Medicine
                phone: 314 - 362 8807
                        Patient #1 30y
Admission: 11/7/02 because of 2 month history of increasing
  dyspnea, nausea, dizziness and tiredness
PMH: congenital urethral stricture, tooth extraction 2 months prior to
  admission
FH: mother 50y, arthritis, father suicide, 3 brothers, no children
PE: VC: 140 lb, 121/75, 100 97oF. Pale, atrophic discolored skin on
  both legs, hyperpigmentation of the neck. Mild splenomegaly
Lab values: WBC 2.9, Hb 4.3 MCV 95.2, Plt 8, Diff: PMN 1000/µl,
  Lyc 180/ µ, rare immature myleocyte, normal electrolytes, liver
  and kidney parameters
DBE: neg, Cytogenetics: normal
Serology for HIV, CMV, EBV and HepB neg
Liver cirrhosis
                    Patient #1 30y
                         cont’
Diagnosis: Hypoplastic Myelodysplastic Syndrome

Treatment:
    1/15/03 IVIG treatment: No response
    2/3/03: ATG & cyclosporin: No response
    BMT : 10/1/03 Fludarabin/Campath/Melphalan, followed by
       10/9/03 cord blood stem cell transplant
    Course of the disease: 11/26/04 Died 6 weeks after BMT
       most likely due to cerebral bleeding
      Bone Marrow Biopsy
           Patient #1




20X            200X
            Erythroid Hyperplasia and
       Anaphase Bridges in the Bone Marrow
             Aspirate from Patient #1




600X             600X            1000X
                       Patient #2 50y
Admission: 7/1/04 because of 6 month history of increasing dyspnea
  and tiredness

PMH: Motor vehicle accident causing multiple fractures of his right leg,
  slow recovery

FH: mother diabetes, died at 60y, father unknown, 2 sisters, 8 children
  from 2 marriages, all healthy (sister registered with NMDP)

PE: VC: 220.6 lb, 121/75, 100 97oF. Pale, some petichiae

Lab values: WBC 1.8, Hb 7.4 MCV 95.2, Plt 5, Diff: PMN 1000/µl, Lyc
  180/ µ, rare immature myleocytes, normal electrolytes, liver and
  kidney parameters
  Serology for HIV, CMV, EBV and HepB neg
Bone Marrow Biopsy
     Patient #2




       20X           200X
Dyserythropoiesis and Micromegakaryocytes
     in the Bone Marrow Aspirate from
                 Patient #2
               Patient #2 50y m
                     cont’
Diagnosis: Hypoplastic Myelodysplastic Syndrome

Treatment: ATG & cyclosporin 7/10/04

Course of the disease: Died due to sepsis 10/04
                               Telomere Length of Peripheral Blood
                               Mononuclear Cells in Patient #1 and 2
                                                         20                                    Normal Caucasian Controls
                                                                                               Patient #2
                                                         18
Relative Telomere Length




                                                                                               Patient #1
                                                                                               Brother of #1
                           (% of 4n control cell line)




                                                         16
                                                                                               Brother of #1
                                                         14

                                                         12

                                                         10

                                                          8

                                                          6

                                                          4

                                                          2

                                                          0
                                                              0   20   40           60    80             100
                                                                            Age (years)
         Telomere length in Myelodysplastic
                    Syndromes
•   Ohyashiki JH, et al. Telomere shortening associated with disease evolution patterns
    in myelodysplastic syndromes. Cancer Res. 1994

•   Boultwood J, et al Telomere length in myelodysplastic syndromes. Am J
    Hematol. 1997

•   Ball SE, et al. Progressive telomere shortening in aplastic anemia. Blood.
    1998

•   Ohyashiki JH, et al Telomere stability is frequently impaired in high-risk groups of
    patients with myelodysplastic syndromes. Clin Cancer Res. 1999

•   Brummendorf TH, et al Telomere length dynamics in normal individuals and in
    patients with hematopoietic stem cell-associated disorders. Ann N Y Acad Sci. 2001

•   Sieglova Z, et al Dynamics of telomere erosion and its association with genome
    instability in myelodysplastic syndromes (MDS) and acute myelogenous leukemia
    arising from MDS: a marker of disease prognosis? Leuk Res. 2004
Telomere stability is frequently impaired in high-risk
groups of patients with myelodysplastic syndromes.
         (Ohyashiki JH, et al Clin Cancer Res. 1999)
Telomere, Telomerase, and Telomere Maintenance



   Telomere




 Chromosome                   Telomerase:
                         Telomerase RNA TERC
                        Telomerase enzyme TERT
              Studies on the Molecular Mechanisms of
                  Bone Marrow Failure at WashU
Wash U St. Louis
Sara Freeman             Collaborations                 Outside Institutions
Shashikant Kulkarni
Honyang Du               Institut Curie, Paris,France   University of Iowa
Philip Mason             Arturo Londoño-Vallejo         Fred Goldman
David Wilson
Monica Bessler           University of Washington       Boston Children's Hospital
                         Neutropenia Registry           Akiko Shimamura
Morey Blinder            David Dale
Robert Hayashi                                         University of California
Steven M. Devine         International Aplastic Anemia Kevin Shannon
John DiPersio            & Myelodysplasia Society
Ravi Vij                 Canadian Aplastic             Duke University
Michael Tomasson         Anemia Society                Sherri Zimmerman

Hereditary Cancer Core                                  Oregon Health Science University
SCC WashU                National Marrow Donor
                         Program (NMDP)                 Grover Bagby
Jennifer Ivanovich
Paul Goodfellow

Genome Sequencing
Center
Mike McLellan
Rick Wilson
  The Molecular Mechanisms of Bone
           Marrow Failure
Aim1
Frequency of excessively short telomeres in
patients with bone marrow failure
Aim 2
Frequency of TERC gene mutations in patients with
bone marrow failure
Aim 3
The pathogenecity of TERC gene mutations
Aim 4
Identification of other genes in bone marrow failure
with short telomeres
                       Project Overview
   Patients at WashU and                              Existing registries
   collaborating institutions

                                BMF patients informed consent



Physical examination              Blood /fibroblast sample        Family history
                                                                    Medical record review

                             Aim 1                Aim 2
                        Telomere length        TERC mutation           Invite family members
                            analysis             analysis                (informed consent)


                    Aim 4                                   Aim 3
          Screening for mutations                    Functional analysis of
          in other telomere genes                      TERC mutation



Blood sample for: mutation analysis,                                          Physical
  blood cell count, telomere length           Medical record review         examination
Telomere Length in Peripheral Blood Mononuclear
 Cells from Individuals with Bone Marrow Failure
                   (Flow FISH)
                                                                  Normal Controls
                            20
                                                                  TERC mutations
                            18                                    DKC1 mutation
 Relative Telomere Length




                                                                  DC no mutation
                            16                                    Bone marrow failure
       (% 4n Cell Line)




                            14
                            12
                            10
                            8
                            6
                            4
                            2
                            0
                                 0   20   40      60         80      100
                                               Age (years)
             Mutations in the TERC RNA

                                         G305A

                                             CR4-CR5
                                              domain

     DTCAG 110-113, DGC 107-108, C204G   G322A

    A117C, C116U                          G288A

    G143A

Pseudoknot                               G450A
  domain                                  Box H/ACA
                                            domain
                          Template       DCC 389-390
C72G, DCT 96- 97
                                         D378-451
                   G58A
                                         C408G
Short Telomeres Signal-Free Ends
in Dyskeratosis Congenita (FISH)
Control 18y            DC 10y
The Three Cardinal Symptoms of
    Dyskeratosis Congenita




                    I. Hyperpigmentation




III. Leukoplakia
                   II. Nail dystrophy   Mazereeuw-
                                        Hautier et al. 1999
Clinical Manifestations due to
    Telomere Dysfunction
Inherited Bone Marrow Failure Syndromes

             Dyskeratosis
            Congenita (DC)

                      Aplastic
Myelodysplastic       Anemia         ?
  Syndrome
     (MDS)             Acute Myelogenous
                             Leukemia
        Paroxysmal nocturnal   (AML)
          hemoglobinuria
             (PNH)

                               Essential
                           thrombocythemia
              Normal             (ET)




     Idiopathic Bone Marrow Failure
                             Summary
              What have we learned so far ?
A subgroup of patients bone marrow failure, including MDS, is caused by
dysfunctional telomere maintenance.

Dysfunctional telomere maintenance may be caused by mutations in the
TERC gene or other genes involved in telomere maintenance.

The diagnosis of dyskeratosis congenita has important implications for
the patient and his family.

We suggest that telomere measurements should be performed in all
individuals with bone marrow failure including MDS.

Much needs to be learned about the disease, its molecular mechanisms,
clinical manifestations, disease progression, inheritance, and response to
treatment.
 Proteins Involved in Telomere Maintenance
                    TERC
                                 Telomerase RNP
   others   Tep1
                      Dyskerin
        TERT
GAR1
                      NHP2
                     NOP10
  Hsp90 p23
                   GAR1




                                            Telomere end maintenance
                                                  (De Lange 2004)
                             Acknowledgement
Wash U St. Louis
Sara Freeman             Collaborations                 Outside Institutions
Shashikant Kulkarni
Honyang Du               Institut Curie, Paris,France   University of Iowa
Philip Mason             Arturo Londoño-Vallejo         Fred Goldman
David Wilson
Monica Bessler           University of Washington       Boston Children's Hospital
                         Neutropenia Registry           Akiko Shimamura
Morey Blinder            David Dale
Robert Hayashi                                         University of California
Steven M. Devine         International Aplastic Anemia Kevin Shannon
John DiPersio            & Myelodysplasia Society
Ravi Vij                 Canadian Aplastic             Duke University
Michael Tomasson         Anemia Society                Sherri Zimmerman

Hereditary Cancer Core                                  Oregon Health Science University
SCC WashU                National Marrow Donor
                         Program (NMDP)                 Grover Bagby
Jennifer Ivanovich
Paul Goodfellow

Genome Sequencing
Center
Mike McLellan
Rick Wilson

								
To top