M OSAICISM MECHANISMS AND IMPACT ON THE DISEASE A NA F ILIPA F REITAS I NÊS F IGUEIREDO M ARIA I NÊS G ONÇALVES M ARIANA F ERREIRA F ACULDADE DE M EDICINA DA U NIVERSIDADE DE C OIMBRA 1. º A NO M ESTRADO I NTEGRADO M EDICINA B IOLOGIA C ELULAR E M OLECULAR II 13 TH M ARCH 2013

S UMMARY  Definition  Mechanism  Types  Germinal  Somatic  Mixed  Associated Diseases  Impact on the Disease  Heteroplasmy  Clinical Cases  Cancer  Down Syndrome  Prenatal Diagnosis and Pseudomosaicism  References 2

M OSAICISM – T HE D EFINITION 3 M OSAICISM “M OSAICISM is a condition in which is notted the presence of two or more different chromosomal complements in the same tissue.” (Azevedo, C.; Sunkel, C.E., 2005) This condition can affect any type of cells. (Reproduced from: Read, A.; Strachan, T., 2011)

Non- disjunction Anaphase lag Premature centromere division M ECHANISM OF F ORMATION 4 M EIOSIS OR M ITOSIS M EIOSIS OR M ITOSIS

M ECHANISM OF F ORMATION COMPLETE P ARTIAL 5 NON - DISJUNCTION IN POST - ZYGOTIC MITOTIC DIVISION (Reproduced from: Azevedo, C.; Sunkel, C.E., 2005)

T YPES OF M OSAICISM 6  G ERMINAL MOSAICISM  S OMATIC MOSAICISM  G ERMINAL AND S OMATIC MOSAICISM

T YPES OF M OSAICISM 7  G ERMINAL M OSAICISM Assintomatic Only germinal cells are affected Could be transmitted to descendents Osteogenesis imperfecta type ll Turner syndrome Duchenne muscular distrophy Haemophylia

T YPES OF M OSAICISM 8  S OMATIC MOSAICISM Sintomatic Somatic cells are affected It’s not inherited Cancer Neurofibrosis Heterochromia iridum Down syndrome Reproduce from: Health Encyclopedia of URMC

S OMATIC VS. G ERMINAL M OSAICISM 9 (A) Hypothetical pedigree of Segmental neurofibromitosis type 1 (AD) and (below) molecular analysis showing somatic mosaicism. (Reproduced from: Youssoufian, H. et al., 2002) (B) Hypothetical pedigree and molecular analysis showing germ-line mosaicism in tuberous sclerosis (AD).

H OW TO DETECT M OSAICISM ? 10  Karyotype analysis  Fluorescent in situ hybridization (FISH)  Array Comparative genomic hybridization (array CGH) Composite array results for mosaic deletions and duplications. Reproduced from [3]3 Examples of FISH results on fetal ovarian cells using two chromosome 21- specific probes. a) Location of the probes near the end of the long arm of chromosome 21. b) Normal cell nucleus showing two dual chromosome 21-specific signals. c, d) T21 cell nuclei showing three dual chromosome 21-specific signals. Reproduced from [1]1

M ENDELIAN D ISORDERS A SSOCIATED W ITH M OSAICISM 11 C LASSIFICATION D ISORDER Metabolic Disorders Tyrosinemia Type I Lesch-Nyhan Conradi-Hunermann-Happle Immune Dysfunction Adenosine Deaminase Deficiency Wiskott-Aldrich Syndrome Clotting DisordersHaemophilias A and B Skeletal Disorders Marfan Syndrome Pseudoachondroplasia Muscle Disorders Duchenne Musclar Dystrophy Congenital Myotonic Dystrophy Chromosomal Instability Bloom Syndrome Fanconi Anemia Tumor Supressor Neurofibromatosis Types I and II Tuberous Sclerosis Skin Disorders Bullous Ichthysiform Erythroderma Incontinentia Pigmenti Endocrine DisordersAndrogen Insensitivity Nervous-System DisordersFriedreich Ataxia Table 1: Examples of additional Mendelian disorders associated with mosaicism Adapted from Youssoufian H. et. al. Human genetics and disease: Mechanisms and consequences of somatic mosaicism in humans. Nature Reviews Genetics 3,

12  [1] The mosaicism effects depend on the:  Stage where the mutation occurs  Nature of the abnormal chromosomes changes  Proportion between normal and abnormal cells  Nature of the affected tissues M OSAICISM : T HE I MPACT ON THE D ISEASE [1] Azevedo, C.; Sunkel, C.E., 2005

H ETEROPLASMY 13  Somatic mosaicism for mitochondrial disorders results from the random segregation of mutant and wild-type mitochondria during mitosis.  Daughter cells with different proportions mutated mitochondria.  The most severe mithocondrial diseases are heteroplasmic. (Reproduced from: Youssoufian, H. et al., 2002)

C ANCER 14  Several recent studies have reported, that the probability of progression to cancer can depend on the degree of mosaicism in a tissue.  Cancer can be caused by mutations in genes that encode or control:  transcription factors  cell cycle checkpoint proteins  growth factors  repair proteins  telomerase  The gene BUB1B, when mutant, causes a chromosomal instability that leads to cancer. it causes mosaic variegated aneuploidy, involving multiple different chromosomes and tissues. S.A. Frank / Journal of Theoretical Biology 223 (2003) 405–412

D OWN S YNDROME 15 Free trisomy 21 Mosaic trisomy 21 Free trisomy 21 in mosaic Meiotic error Post-zygotic non-disjunction Cell rescue All cells are trisomic Two different lines of cells: Normal and Trisomic Robertsonian translocation Kariotype: 46, XX or 46, XY

T HE M OSAICISM I MPACT ON D OWN S YNDROME 16  Results in a highly variable clinical phenotype depending on:  the tissues involved  proportion of trisomic cells  the sequence of events leading to the mosaicism

T HE M OSAICISM I MPACT ON D OWN S YNDROME 17 Leukemia Alzheimer’s Disease Immunodeficiency Infections Solid Cancers Type 1 diabetes Hypothyroidism Asthma Premature aging Increases Decreases According to Hultén et al. [2]2

18 Amniocentisis Different cellular lines 2 or more individual cultures 1 individual culture Pseudomosaicism True Mosaicism P RENATAL D IAGNOSIS AND P SEUDOMOSAICISM

R EFERENCES 23/02/13:  chromosomal-disorders chromosomal-disorders-867  90/Default.aspx 90/Default.aspx  LY LY     html html    osaicism&hl=pt- PT&sa=X&ei=tU8pUaqILoiShgfuoIDIAw&ved=0CEsQ6AEwBQ#v=one page&q=mosaicism&f=false osaicism&hl=pt- PT&sa=X&ei=tU8pUaqILoiShgfuoIDIAw&ved=0CEsQ6AEwBQ#v=one page&q=mosaicism&f=false 19

R EFERENCES 24/02/13:  durante-o-desenvovimento-somtico durante-o-desenvovimento-somtico  mosaicismocromossomico.htm mosaicismocromossomico.htm  PT&lr=&id=jkw3y4DmrM4C&oi=fnd&pg=PA2&dq=mosaici smo+gen%C3%A9tico&ots=ZmNNg537Iz&sig=ZEp-bx- SUu_Ft_b63naGJy2ydRA&redir_esc=y#v=onepage&q=mosa icismo%20gen%C3%A9tico&f=false PT&lr=&id=jkw3y4DmrM4C&oi=fnd&pg=PA2&dq=mosaici smo+gen%C3%A9tico&ots=ZmNNg537Iz&sig=ZEp-bx- SUu_Ft_b63naGJy2ydRA&redir_esc=y#v=onepage&q=mosa icismo%20gen%C3%A9tico&f=false   px?ContentTypeID=90&ContentID=P px?ContentTypeID=90&ContentID=P

R EFERENCES 21 25/02/13  [1] Hultén MA, Patel SD, Tankimanova M, Westgren M, Papa- dogiannakis N, Jonsson AM, Iwarsson E. On the origin of trisomy 21 Down syndrome. Mol. Cytogenet.2008;1:21. (  [2] Hultén MA, Jonasson J, Nordgren A, Iwarsson E. On Germinal and Somatic Trisomy 21 Mosaicism: How Common is it, What are the Implications for Individual Carriers and How Does it Come About?. Curr Genomics September; 11(6): 409–419. (  [3] Conlin LK, Thiel BD, Bonnemann CG, Medne L, Ernst LM, Zackai EH, Deardorff MA, Krantz ID, Hakonarson H, Spinner NB. Mechanisms of mosaicism, chimerism and uniparental disomy identified by single nucleotide polymorphism array analysis. Hum Mol Genet April 1; 19(7): 1263–1275. (

R EFERENCES 22 27/02/13:   diagnosi-prenatale.aspx diagnosi-prenatale.aspx  osaic_ro.htm osaic_ro.htm  A. Paskulin, Giorgio; B. Lorenzen, Marina et all. (2011) Importance of the fibroblast chromosomal analysis in suspected cases of mosaicism: experience of a clinical Genetics service. Revista Paulista de Pediatria.; 29(1):73-9.  Cunningham, Gary F.; Leveno, Kenneth J. et all. (2012) Williams Obstetrics. 23 rd Edition. McGraw-Hill. Cap 12, P.275,276.  Pierce, Benjamin A.; (2004) Genética-Um Enfoque Conceitual. Cap 9, P  Regateiro, Fernando J. (2007) Manual de Genética Médica. Cap IV.  Rodríguez-Santiago, Benjamín; Malats, Núria et all. (2010) Mosaic Uniparental Disomies and Aneuploidies as Large Structural Variants of the Human Genome. The American Journal of Human Genetics. July 9. P.87, 129–138.

R EFERENCES 23 03/03/13  Azevedo, C.; Sunkel, C.E. (2005). Meiose e Aneuploidia in Biologia Celular e Molecular (pp ). LIDEL-Edições Técnicas, Lisboa (Ed.)  Lewis, Ricki. (2008) Human Genetics – Concepts and Applications; 8th edition; chapters 5 (pp.96-98) and 18 (pp ). McGraw-Hill.  Read, A.; Strachan, T. (2011). Human Molecular Genetics; 4th edition; chapter 3; Garland Science  Youssoufian, H. et al. (2002). Mechanisms and consequences of somatic mosaicism in humans (pp ). Nature Reviews Genetics 3.  Frank SA. Somatic mosaicism and cancer: inference based on a conditional Luria–Delbruck distribution. Department of Ecology and Evolutionary Biology, University of California. Journal of Theoretical Biology 223 (2003) 405–412 (  

24 Q UESTIONS ?