Fanconi's Anemia

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Fanconi's Anemia

  1. 1. Fanconi AnemiaFanconi Anemia Priya GopalanPriya Gopalan April 7, 2006April 7, 2006
  2. 2.  CaseCase  Clinical FeaturesClinical Features  DiagnosisDiagnosis  FA pathwayFA pathway  ManagementManagement  ConclusionsConclusions
  3. 3. CaseCase  A 21 year old Mexican woman with aA 21 year old Mexican woman with a history of anemia, presented to a localhistory of anemia, presented to a local clinic with a positive home pregnancy test.clinic with a positive home pregnancy test. After confirming her pregnancy (she wasAfter confirming her pregnancy (she was approximately 13 weeks pregnant), sheapproximately 13 weeks pregnant), she had several labs drawn, including a CBC.had several labs drawn, including a CBC. She was found to be pancytopenic, andShe was found to be pancytopenic, and was told to come to BJC for admission.was told to come to BJC for admission.
  4. 4. CaseCase  She complained of fatigue and easyShe complained of fatigue and easy bruising for many months, but nobruising for many months, but no epistaxis, hematochezia, melena orepistaxis, hematochezia, melena or hematuria. Furthermore, her menstrualhematuria. Furthermore, her menstrual cycles had been regular and moderatecycles had been regular and moderate until 3 months ago.until 3 months ago.
  5. 5. CaseCase  Past Medical History: She was first told that shePast Medical History: She was first told that she was anemic 5 years ago, in Mexico. At thatwas anemic 5 years ago, in Mexico. At that time, she had a bone marrow biopsy performed.time, she had a bone marrow biopsy performed. She is not sure what it showed, but she was toldShe is not sure what it showed, but she was told to take Proverone (medroxyprogesterone) onceto take Proverone (medroxyprogesterone) once a day, which she was unable to afford.a day, which she was unable to afford.  Medications: NoneMedications: None  Allergies: NoneAllergies: None
  6. 6. CaseCase  Social History: She moved to the U.S. 2Social History: She moved to the U.S. 2 years ago, from Mexico. She is single andyears ago, from Mexico. She is single and works as a housekeeper. She denies anyworks as a housekeeper. She denies any tobacco, alcohol or drug use.tobacco, alcohol or drug use.
  7. 7. CaseCase  Family History:Family History:  She has 3 siblings in the U.S., and 10 siblingsShe has 3 siblings in the U.S., and 10 siblings in Mexico. One sister in Mexico, who is nowin Mexico. One sister in Mexico, who is now 15 years old, was just diagnosed with anemia,15 years old, was just diagnosed with anemia, and had a bone marrow biopsy. She is notand had a bone marrow biopsy. She is not sure what it showed.sure what it showed.  No family history of hematological disorders,No family history of hematological disorders, cancers or early deaths. Her grandparentscancers or early deaths. Her grandparents and parents are alive and healthy.and parents are alive and healthy.
  8. 8. CaseCase  Physical examination:Physical examination:  Height: 5’0”Height: 5’0”  Significant only for bilaterally short thumbsSignificant only for bilaterally short thumbs  No dermatologic abnormalitiesNo dermatologic abnormalities  Labs:Labs:  WBC: 2.1 (41%N, 53%L; ANC 900)WBC: 2.1 (41%N, 53%L; ANC 900)  Hemoglobin / Hematocrit: 4.9/14.2 (MCV 111)Hemoglobin / Hematocrit: 4.9/14.2 (MCV 111)  Platelets: 17,000Platelets: 17,000
  9. 9. CaseCase  Other labs:Other labs:  CMP WNL (Cr 0.4)CMP WNL (Cr 0.4)  Vitamin B12 and folic acid WNLVitamin B12 and folic acid WNL  Reticulocyte 2.4%Reticulocyte 2.4%  Hepatitis panel/HIV negative, ANA negativeHepatitis panel/HIV negative, ANA negative  Peripheral smear: normal-appearing WBC,Peripheral smear: normal-appearing WBC, RBC and platelets, but greatly reduced inRBC and platelets, but greatly reduced in numbernumber
  10. 10. CaseCase  Bone Marrow Biopsy:Bone Marrow Biopsy:  Markedly hypocellular marrow, with markedlyMarkedly hypocellular marrow, with markedly decreased trilineage hematopoiesis,decreased trilineage hematopoiesis, consistent with aplastic anemia (cellularityconsistent with aplastic anemia (cellularity <5%)<5%)  No overt dysplastic featuresNo overt dysplastic features  Cytogenetics were pendingCytogenetics were pending
  11. 11. CaseCase  A diagnosis of Fanconi Anemia wasA diagnosis of Fanconi Anemia was suspected based on:suspected based on:  History of “anemia” at age 16History of “anemia” at age 16  History of “anemia” in a sister, at age 15History of “anemia” in a sister, at age 15  Short statureShort stature  Shortened thumbs bilaterallyShortened thumbs bilaterally  PancytopeniaPancytopenia  Bone marrow hypocellularityBone marrow hypocellularity
  12. 12. Fanconi AnemiaFanconi Anemia  Inherited recessive diseaseInherited recessive disease  Usually autosomal recessiveUsually autosomal recessive  Recently, an X-linked form has beenRecently, an X-linked form has been described (Meetei et al 2004)described (Meetei et al 2004)  12 different complementation groups12 different complementation groups  Determined by somatic cell hybridizationDetermined by somatic cell hybridization analysisanalysis  11 genes cloned11 genes cloned
  13. 13. FA complementation groups and FA genesFA complementation groups and FA genes FAFA complementationcomplementation groupgroup FA geneFA gene Approx. frequencyApprox. frequency in FA patients (%)in FA patients (%) ChromosomalChromosomal LocationLocation AA FANCAFANCA 6060 16q24.316q24.3 BB FANCBFANCB RareRare Xp22.31Xp22.31 CC FANCCFANCC 1515 9q22.39q22.3 D1D1 BRCA2BRCA2 55 13q12.313q12.3 D2D2 FANCD2FANCD2 55 3p25.33p25.3 EE FANCEFANCE RareRare 6p21.36p21.3 FF FANCFFANCF RareRare 11p1511p15 GG FANCGFANCG 1010 9p139p13 II UnknownUnknown RareRare UnknownUnknown JJ BRIP1BRIP1 RareRare 17q23.217q23.2 LL FANCLFANCL RareRare 2p162p16 MM FANCMFANCM RareRare 14q21.214q21.2 from Kennedy and D’Andrea, Genes & Development, 2005
  14. 14. Clinical featuresClinical features  Incidence is 3/1,000,000Incidence is 3/1,000,000  Heterozygote frequency ~1/300 in U.S. and EuropeHeterozygote frequency ~1/300 in U.S. and Europe  Ashkenzai Jewish population carrier frequency 1/89Ashkenzai Jewish population carrier frequency 1/89  Afrikaners carrier frequency 1/83Afrikaners carrier frequency 1/83  Median age at diagnosis is 5-7Median age at diagnosis is 5-7 (Alter et al., Blood 2003)(Alter et al., Blood 2003)  Median survival is 20-30 yrs.Median survival is 20-30 yrs. (Alter et al., Blood 2003)(Alter et al., Blood 2003)  Phenotypic variability occurs even within familiesPhenotypic variability occurs even within families (Koc et al., Br J Haem 1999)(Koc et al., Br J Haem 1999)
  15. 15. Clinical FeaturesClinical Features  Characterized byCharacterized by  Congenital abnormalitiesCongenital abnormalities  Progressive bone marrow failureProgressive bone marrow failure  Increased risk of malignanciesIncreased risk of malignancies
  16. 16. Frequency of abnormalities in FA Abnormality Frequency (%) Skeletal (radial ray, hip, vertebral scoliosis, rib) 71 Skin pigmentation (café au lait, hyper- and hypopigmentation) 64 Short stature (median height 5th %ile) 63 Eyes (microphthalmia) 38 Renal and urinary tract 34 Male genitalia 20 Mental retardation 16 Gastrointestinal (eg, anorectal, duodenal atresia) 14 Cardiac abnormalities 13 Hearing 11 Central nervous system (eg, hydrocephalus, septum pellucidum) 8 No abnormalities 30 Tischkowitz, M D et al. J Med Genet 2003;40:1-10 (taken from Dokal, 2000)
  17. 17. Copyright ©2003 BMJ Publishing Group Ltd. Tischkowitz, M D et al. J Med Genet 2003;40:1-10 (A) Typical radial ray abnormalities and (B) cafe au lait patches and hypopigmentation
  18. 18.  Progressive bone marrow failureProgressive bone marrow failure  Most common etiology of inherited boneMost common etiology of inherited bone marrow failuremarrow failure • Others include dykeratosis congenita,Others include dykeratosis congenita, amegakaryocytic thrombocytopenia, Schwachman-amegakaryocytic thrombocytopenia, Schwachman- Diamond syndromeDiamond syndrome  Increased risk of MDS and AML (15,000x)Increased risk of MDS and AML (15,000x)  Many have monosomy 7, or duplication of 1qMany have monosomy 7, or duplication of 1q (Auerbach et al., Cancer Genet Cytogenet 1991)(Auerbach et al., Cancer Genet Cytogenet 1991) Clinical FeaturesClinical Features
  19. 19. Clinical FeaturesClinical Features  Increased risk of solid tumor formationIncreased risk of solid tumor formation (hepatic, esophageal, oropharyngeal,(hepatic, esophageal, oropharyngeal, vulvar)vulvar)  Average age at diagnosis is 23*Average age at diagnosis is 23*  Cumulative incidence ~30% by age 45**Cumulative incidence ~30% by age 45** *Shimamura et al., Gene Reviews 2002 (genetests.org) **Alter et al. Blood 2003
  20. 20. DiagnosisDiagnosis  Pts. with congenital abnormalities arePts. with congenital abnormalities are often diagnosed as neonates/infantsoften diagnosed as neonates/infants  Others may be diagnosed whenOthers may be diagnosed when hematological problems occurhematological problems occur  Median age of onset of pancytopenia is 7Median age of onset of pancytopenia is 7 (Butturini et al., Blood 1994)(Butturini et al., Blood 1994)  Usually normal CBC at birthUsually normal CBC at birth  First develop macrocytosis, thenFirst develop macrocytosis, then thrombocytopenia, and eventuallythrombocytopenia, and eventually neutropenianeutropenia
  21. 21. DiagnosisDiagnosis  Based on chromosomal hypersensitivity toBased on chromosomal hypersensitivity to cross-linking agentscross-linking agents  Chromosome fragility test: Mitomycin C (MMC) orChromosome fragility test: Mitomycin C (MMC) or diepoxybutane (DEB) added to lymphoctyes –diepoxybutane (DEB) added to lymphoctyes – increases the number of chromosome breaks andincreases the number of chromosome breaks and radial structuresradial structures • Very specific for FA, regardless of severity of diseaseVery specific for FA, regardless of severity of disease • Can do chromosome breakage analysis on amniotic cells,Can do chromosome breakage analysis on amniotic cells, chorionic villus cells or fetal bloodchorionic villus cells or fetal blood
  22. 22. DiagnosisDiagnosis  Difficult to screen using molecular testing due to multipleDifficult to screen using molecular testing due to multiple complementation groups and heterogeneity of mutationscomplementation groups and heterogeneity of mutations  Afrikaners: 60% of 46 pts. had deletion of exons 12-31 inAfrikaners: 60% of 46 pts. had deletion of exons 12-31 in FANCA (Tipping et al., PNAS 2001)FANCA (Tipping et al., PNAS 2001)  Ashkenazi’s: Many have mutation IVS4+4AAshkenazi’s: Many have mutation IVS4+4A  T (altered spliceT (altered splice site and deletion of exon 4) in FANCC (Gillio et al., Blood 1997)site and deletion of exon 4) in FANCC (Gillio et al., Blood 1997)  Also used for carrier testing and prenatal diagnosisAlso used for carrier testing and prenatal diagnosis
  23. 23. Niedernhofer et al., Science 2005
  24. 24. FA cells were treated with mitomycin C and harvested in metaphase. Typical abnormalities include radial formation (green circle) and chromosome breaks (red arrows).
  25. 25. FA pathwayFA pathway  During S-phase, DNA replication isDuring S-phase, DNA replication is mediated by DNA polymerases acting atmediated by DNA polymerases acting at multiple replication forksmultiple replication forks  Alkylating agents such as MMC and DEBAlkylating agents such as MMC and DEB induce cross-links, halting replication atinduce cross-links, halting replication at the forksthe forks  When replication is halted due to cross-When replication is halted due to cross- linking, the FA pathway is activatedlinking, the FA pathway is activated
  26. 26. Activation of the FA pathwayActivation of the FA pathway  Activated during the S phase in response toActivated during the S phase in response to DNA replication fork arrestDNA replication fork arrest  Leads to local single-stranded DNALeads to local single-stranded DNA  Single-stranded DNA binds to, among other proteins,Single-stranded DNA binds to, among other proteins, ATR (ataxia telangiectasia and RAD3-related protein,ATR (ataxia telangiectasia and RAD3-related protein, an S-phase checkpoint kinase)an S-phase checkpoint kinase)  ATR phosphorylates many DNA repair andATR phosphorylates many DNA repair and checkpoint proteins, including CHK1 (Checkpointcheckpoint proteins, including CHK1 (Checkpoint Kinase 1)Kinase 1)  ATR and CHK1 are somehow involved in activatingATR and CHK1 are somehow involved in activating the FA pathway (Seckel syndrome)the FA pathway (Seckel syndrome) Andreassen et al., Genes and Dev 2004Andreassen et al., Genes and Dev 2004
  27. 27. FA gene productsFA gene products  Complex 1 may detect stalled replication forksComplex 1 may detect stalled replication forks  It appears to monoubiquitinate FANCD2 (at Lys 561)It appears to monoubiquitinate FANCD2 (at Lys 561) • FANCL may be the catalytic subunitFANCL may be the catalytic subunit  Complex 2 may be involved in DNA repairComplex 2 may be involved in DNA repair  FANCD2-Ub relocalizes to chromatin (dependent onFANCD2-Ub relocalizes to chromatin (dependent on BRCA1)BRCA1)  It associates with/may promote binding of other DNAIt associates with/may promote binding of other DNA damage repair proteins, including FANCD1 (BRCA2),damage repair proteins, including FANCD1 (BRCA2), BRCA1, RAD51, PCNA, NBS1, and possibly FANCJBRCA1, RAD51, PCNA, NBS1, and possibly FANCJ ((BRCA1-Interacting Protein [BRIP1]BRCA1-Interacting Protein [BRIP1])) • DNA repair pathways may be involved in the pathogenesis ofDNA repair pathways may be involved in the pathogenesis of inherited forms of breast cancerinherited forms of breast cancer Kennedy and D’Andrea, Genes and Dev 2005,Kennedy and D’Andrea, Genes and Dev 2005, Fei et al., Cell Cycle 2005Fei et al., Cell Cycle 2005
  28. 28. Richard D. Kennedy et al. Genes Dev. 2005; 19: 2925-2940 Schematic interaction of the FA pathway L=catalytic element? =BRIP1 and BRCA1, RAD51, PCNA, NBS1
  29. 29. Richard D. Kennedy et al. Genes Dev. 2005; 19: 2925-2940 A schematic diagram depicting how the FA pathway may function to coordinate the cellular response to replication fork arrest following DNA damage
  30. 30. Richard D. Kennedy et al. Genes Dev. 2005; 19: 2925-2940, adapted from Niedzwiedz et al. Mol. Cell 2004; 15: 607-620. A simplified model of FA-mediated cross-link repair that involves nucleotide excision repair (NER), translesion synthesis (TLS), and homologous recombination (HR)
  31. 31. Initial managementInitial management  Refer for genetic counselingRefer for genetic counseling  Testing of siblingsTesting of siblings  Renal ultrasound, hearing test, eye examRenal ultrasound, hearing test, eye exam  Endocrine evaluation if evidence of growthEndocrine evaluation if evidence of growth failure (check growth hormone levels,failure (check growth hormone levels, TSH)TSH)  Referral to hand surgeon for radial rayReferral to hand surgeon for radial ray defectsdefects  Bone marrow biopsyBone marrow biopsy
  32. 32. ManagementManagement  Bone marrow failureBone marrow failure  TransfusionsTransfusions  Androgens (e.g. oral oxymethalone) – can improveAndrogens (e.g. oral oxymethalone) – can improve blood counts in 50% of pts.blood counts in 50% of pts. • Side effects: Masculinization, acne, hyperactivity, prematureSide effects: Masculinization, acne, hyperactivity, premature closure of epiphyses, liver toxicity, hepatic adenomasclosure of epiphyses, liver toxicity, hepatic adenomas  Growth factors (G-CSF, CM-CSF) – should not beGrowth factors (G-CSF, CM-CSF) – should not be used in patients with clonal cytogenetic abnormalitiesused in patients with clonal cytogenetic abnormalities  Bone marrow transplantationBone marrow transplantation • FA cells are very sensitive to radiation and alkylating agentsFA cells are very sensitive to radiation and alkylating agents – can use greatly reduced doses– can use greatly reduced doses • 2-yr. survival 70% for allo;* 20-40% for MUD**2-yr. survival 70% for allo;* 20-40% for MUD** *Guardiola et al. Bone Marrow Transplant 1998; **MacMillan et al., Br J Haematol 2000
  33. 33. ManagementManagement  Surveillance for solid tumorsSurveillance for solid tumors  42% risk of malignancy 20 yrs. after42% risk of malignancy 20 yrs. after transplant (Deeg et al. Blood 1996)transplant (Deeg et al. Blood 1996)  Annual gyn examsAnnual gyn exams  If malignancy is diagnosed, treatment isIf malignancy is diagnosed, treatment is limited by the increased sensitivity to DNA-limited by the increased sensitivity to DNA- damaging chemotherapeutic agentsdamaging chemotherapeutic agents
  34. 34. Management - Gene therapyManagement - Gene therapy  Goal is to permanently correct hematologicalGoal is to permanently correct hematological manifestations by transducing hematopoieticmanifestations by transducing hematopoietic progenitor cells with a vector containing theprogenitor cells with a vector containing the deficient genedeficient gene  Knockout mice with FANCC using retroviralKnockout mice with FANCC using retroviral vectors - phenotypic correctionvectors - phenotypic correction (Gush et al., Blood(Gush et al., Blood 2000)2000)  Clinical trial disappointing (Liu et al., Human GeneClinical trial disappointing (Liu et al., Human Gene Therapy 1999)Therapy 1999)  Knockout mice with FANCA and FANCC usingKnockout mice with FANCA and FANCC using lentiviral vectors – more promising (integrateslentiviral vectors – more promising (integrates into the genome)into the genome) (Galimi et al. Blood 2002)(Galimi et al. Blood 2002)
  35. 35. ConclusionsConclusions  FA is characterized by congenital abnormalities,FA is characterized by congenital abnormalities, bone marrow failure and predisposition tobone marrow failure and predisposition to malignancies (leukemias and solid tumors)malignancies (leukemias and solid tumors)  Diagnosis is based on hypersensitivity to cross-Diagnosis is based on hypersensitivity to cross- linking agents such as DEB and MMClinking agents such as DEB and MMC  FA pathway is involved in repair of DNA cross-FA pathway is involved in repair of DNA cross- linkslinks  FANCD1 is BRCA2, FANCJ is BRIP1 and FANCD2FANCD1 is BRCA2, FANCJ is BRIP1 and FANCD2 associates with BRCA1 and BRIP1, suggesting a roleassociates with BRCA1 and BRIP1, suggesting a role for DNA repair pathways in the pathogenesis offor DNA repair pathways in the pathogenesis of inherited breast cancersinherited breast cancers  Treatment includes bone marrow transplantationTreatment includes bone marrow transplantation
  36. 36. CaseCase  The patient’s FA test was negative. SheThe patient’s FA test was negative. She does, however, have aplastic anemia, anddoes, however, have aplastic anemia, and does want to keep her baby. She met withdoes want to keep her baby. She met with Dr. DiPersio this week to discussDr. DiPersio this week to discuss transplantation.transplantation.
  37. 37. Richard D. Kennedy et al. Genes Dev. 2005; 19: 2925-2940 The FA pathway may function to specifically coordinate more than one pathway following cross-linking damage, whereas IR and UV damage can be repaired through other pathways
  38. 38. Figure 1. Some Features of Fanconi's Anemia. The physical and cytogenetic findings in some patients with Fanconi's anemia are shown. Panel A shows the characteristically short thumb; Panel B shows a cafe au lait spot; and Panel C shows chromosomal breaks as revealed by cytogenetic analysis (A indicates chromatid breaks, B chromatid fragments, and C a dicentric chromosome). Other common clinical manifestations include short stature, skin hyperpigmentation, pancytopenia, and renal anomalies.

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