Strutturazione della

consulenza genetica

nella SLA familiare e sporadicaMarcella Zollino

Istituto di Genetica Medica

Universit Cattolica Sacro Cuore Policlinico A. Gemelli, Roma

Lecce, 20 gennaio 2015

Sclerosi Laterale Amiotrofica(SLA)Forme familiari

Forme sporadiche

SLA FAmiliare(FALS)AUTOSOMICO-DOMINANTE

Autosomico-recessivo

X-linked

EREDITARIETA

AUTOSOMICO-DOMINANTE

Ereditariet autosomico-dominante (AD)Il soggetto affetto eterozigote per la mutazione

2) Affetti: maschi e femmine (1:1)

Ereditariet autosomico-dominante (AD)

3) Genitore affetto: 50% dei figli affetti trasmissione verticale genitore-figlio

4) Un genitore sano non trasmette la malattia

Ereditariet autosomico-dominante (AD)4) Se genitori sani: prima mutazione

caso sporadico nella famiglia

Malattie autosomiche dominanti. Rischio riproduttivo relativo

Albero genealogico con esempio di trasmissione verticale di una mutazione autosomica dominante

Irregolarit della trasmissione autosomica dominanteSalto di generazione per difetto di penetranza

EREDITARIETA

AUTOSOMICO-RECESSIVA

Ereditariet autosomico-recessiva (AR)Il soggetto affetto omozigote per la mutazione

- eterozigote composto (alleli mutati diversi)

- omozigote (stesso allele mutato)2) Genitori sani, ma portatori eterozigoti di mutazione

Ereditariet autosomico-recessiva (AR)3) Affetti: sia maschi che femmine (geni autosomici)

Ereditariet autosomico-recessiva (AR)4) Rischio riproduttivo per genitori eterozigoti:

25 % figli affetti 25 % figli omozigoti sani

50 % figli eterozigoti per la mutazione

Rischio di ricorrenza in ogni futura gravidanza: 25%

Ereditariet autosomico-recessiva (AR)5) Consanguineit nei genitori

mutazioni rare stesso allele in omozigosi

N.B. Quanto pi frequente lo stato di portatore eterozigote, meno influente la consanguineit nei genitori

EREDITARIETA X-LINKED

La maggior parte delle mutazioni presenti sul cromosoma X sono recessive e quindi si manifestano solo nei maschi (per la loro condizione di emizigoti) -La presenza della malattia dipende dal sesso (sono malati solo i maschi)

-La malattia non si trasmette mai da maschio malato a figlio ma da maschio malato a circa la met dei nipoti maschi, attraverso femmine sane (che sono portatici).

Malattie a trasmissione X-linked. Rischi riproduttivi relativi a:A) femmina eterozigote e maschio emizigote normale

2) Assenza di trasmissione da maschio malato

a figlio maschio malato

3) Maschio malato: 100% di figlie femmine portatrici

Sclerosi Laterale Amiotrofica(SLA)Definizione SLA familiare (FALS) e SLA sporadica (SALS)

Sclerosi Laterale Amiotrofica(SLA)Definizione SLA familiare (FALS) e SLA sporadica (SALS) Le FALS sono tutte mendeliane?

Sclerosi Laterale Amiotrofica(SLA)Definizione SLA familiare (FALS) e SLA sporadica (SALS) Le FALS sono tutte mendeliane?Ipotesi multigenica delle SALS e FALS: fatti e prospettive

Sclerosi Laterale Amiotrofica(SLA)Definizione SLA familiare (FALS) e SLA sporadica (SALS) Le FALS sono tutte mendeliane?Consulenza genetica nelle FALS e nelle SALS con mutazioneIpotesi multigenica delle SALS e FALS fatti e prospettive

Sclerosi Laterale Amiotrofica(SLA)Definizione SLA familiare (FALS) e SLA sporadica (SALS) Tempo per esame genetico sistematico nelle SALS? Le FALS sono tutte mendeliane?Consulenza genetica nelle FALS e nelle SALS con mutazioneIpotesi multigenica delle SALS e FALS fatti e prospettive

ALSDefinizione FALS e di SALS

8 prospective studies: 5.1%Rome ALS Clinic center:-980 patients-5.8% (57 pat.) FALS

5.7%

FALS.Famiglia con mutazione C9ORF72

In tutti i pazienti con sospetta SLA, atrofia muscolare progressiva, sclerosis laterale primaria o demenza fronto-temporale, bisogna raccogliere una dettagliata storia familiare genitori fratelli nonni, cugini zii

PROBABLE FALSPOSSIBLE FALSAB

53 famiglie con SLA25 % delle SLA ha una SLA familiare definita

SLA FamiliareSLA Familiare

probabileSLA sporadicadefinitaSLA Familiare

possibile

unknownC9ORF72SOD1TARDBPFUS171 FALS (ITALSGEN)Mutazioni nel 61%C9ORF72SOD1TARDBPFUS112 FALS (Kings College)OPTNVCPMutazioni nel 55%unknown

Grafico1

45

38

13

6

1

1

73

Foglio1

C9ORF7245

SOD138

TARDBP13

FUS6

OPTN1

VCP1

UNKNOWN73

Foglio1

Foglio2

Foglio3

Grafico2

29

27

1

4

0

0

51

Foglio1

C9ORF7245

SOD138

TARDBP13

FUS6

OPTN1

VCP1

UNKNOWN73

C9ORF7210

SOD17

TARDBP1

FUS1

ANG0

ATXN-23

OPTN0

UNKNOWN31

King

C9ORF7229

SOD127

TARDBP1

FUS4

OPTN0

VCP0

UNKNOWN51

Foglio1

Foglio2

Foglio3

SLA Familiare definitaSLA Familiare A BSLA sporadica SLA Familiare possibile

61%

61%

27%

11% 81% 66% 55% 40%

FALSSALSSLA sporadiche e familiari sono clinicamente indistinguibili Inclusioni TDP-43-positive sono presenti in entrambiTutti i geni trovati nelle SLA familiari son stati identificati anche nelle forme sporadiche

61/554: 11%

SLA sporadica61/554: 11%3.2%2.2%2%

Grafico2

0.89

0.021

0.027

0.006

0.012

0.006

0.017

0.025

11%

89,0%

Foglio1

not mutatedSOD1TARDBPFUSANGOPTNATXN-2C9ORF72

89.0%2.1%2.7%0.6%1.2%0.6%1.7%2.5%

Foglio1

0

0

0

0

0

0

0

0

Foglio2

0

0

0

0

0

0

0

0

Foglio3

SLA Familiare definitaSLA Familiare probabile A BSLA sporadica SLA Familiare possibile

61%

61%

27%

11% 81% 66% 55% 40% 11%28%

Spiegazioni PossibiliLa diagnosi di SLA sporadica erronea; sono in realt familiariNon ci sono conoscenze sui familiariFamiliari hanno avuto la SLA ma non stata diagnosticataFamiliari deceduti per altre malattie prima di sviluppare la SLALe famiglie sono piccole

Studi genetici in 8 famiglieSpiegazioni possibili: le mutazioni sono de novo

Possibili spiegazioni: pleiotropia

SOD1: p.E133del, p.L67P, p.D11Y, p.D90ATARDBP: p.G294VC9ORF72: 2 pazientiPossibili spiegazioni Bassa penetranzaLa mutazione dei casi sporadici era presente in familiari asintomatici in 7/8 famiglie:

92 y*onset 55 yE133del*L67PSOD176 yonset 36 yC9orf7278 y*onset 47 y

p.G294V TARDBP 90 y

penetranzaConcetto generico difficilmente applicabile a singoli pedigrees nel setting clinico Paradigma SOD1: 170 mutazioni molte delle quali identificate in una o due famiglie. Penetranza (patogenicit?) difficilmente definibile(eccezioni A4V)C9ORF72: la mutazione pi frequente nelle SLA sporadiche

37.6% (95% CI 33.7-41.69)5.8% (95% CI 4.4-7.4)6.3% (95% CI 5.6-7.1)25.1% (95% CI 20.9-29.6)

Espansione patologica in 11/7579 controlli sani: 0.15%1/600 individuiIn Italia: 100.000 persone

Possibili spiegazioni della penetranza variabile: mutazioni multiple

64 y38 yp.I46V ANG C9ORF72 expansion 70 yC9ORF72 expansion + p.I46V ANG**

Mutazioni multiple1 paziente: C9ORF72+ANG1 paziente: SOD1+ANG

La frequenza di mutazioni doppie osservate in pazienti (0.4) era circa 7 volte maggiore di quella attesa per caso (0.05)

Multiple mutations in 5/97 FALS

Lazione selettiva responsabile di una marcata eterogeneit allelicaSpecifiche per differenti popolazioni (drift)

SLA familareSLA sporadica28% mutazioni rare21%mutazioni comuni50% delle SLA sporadiche

MATR3ATXN2 normaleATXN2 32 triplette

6471 patientsANG variants: 0.46%

7678 Controls: 0.04%

SLA familiareSLA sporadicaMonogenicaDigenicaOligogenicaMultigenica

Clinical DNA analysis for gene mutations should only be performed in cases with a known family history of ALS, and in sporadic ALS cases with the characteristic phenotype of the recessive D90A mutation (GCPP).

Clinical DNA analysis for gene mutations should not be performed in cases with sporadic ALS with a typical classical ALS phenotype

In familial or sporadic cases where the diagnosis is uncertain, SMN, androgen receptor or TARDBP, FUS, ANG or SOD1 DNA analysis may accelerate the diagnostic process

Before blood is drawn for DNA analysis, the patient should receive genetic counselling. Give the patient time for consideration. DNA analysis should be performed only with the patients informed consent (GCPP).

Presymptomatic genetic testing should only be per- formed in rst-degree adult blood relatives of patients with a known gene mutation. Testing should only be performed on a strictly voluntary basis as outlined and should follow accepted ethical principles . . Results of DNA analysis performed on patients and their relatives as part of a research project should not be used in clinical practice or disclosed to unaected rela- tives.Theresearchresultsshouldbekeptinaseparatele and not in the patients standard medical chart (GCPP).

Cattolica. Roma

FALS225 indexSALS725mean age of onset55 years56 yearsMedian age of onset55 y (range 21- 85)58 y (range 21-87)M/F1.41.4median disease duration33 m (range 3-336)48 m (range 1-354)

FALSSALS553mean age of onset55. 8 years (53 index)54.3 years (110 index+r)60.25 years

British Twin Study: 10.872 certificati di morte di pz con SLA - identificate 75 coppie di gemelli di cui almeno uno con SLASwedish Twin Register: su 86.411 coppie di gemelli identificati 73 coppie di gemelli, di cui almeno uno con SLA

Ereditabilit : 0,61 (0,38-0,78)Componente ambientale: 0,39 (0,22-0,62)

A gene disease with a penetrance of:0.9 will seem sporadic in one-third of cases0.5 will seem sporadic in two-thirds of cases

Psycosis

Double mutations1 patient: C9ORF72+ANG1 patient: SOD1+ANG

the frequency of double mutation found in patients (0.4) was approximately 7 times greater than would be expected by chance (0.05)

Multiple mutations in 5/97 FALS

Stdio di 8 famiglie di SLA sporadiche

Spiegazioni possibili La mutazione de novo

172 mutazioni (ALSoD): missenso, non senso, delezioniNo hot spot mutazionaleQuasi tutte in eterozigosi (D90A omozigosi)Mai riportato coinvolgimento delle funzioni cognitiveSOD1

C9ORF72: 3SOD1: 3TARDBP: 1FUS; 1C9ORF72: 5SOD1: 2ATXN2: 1C9ORF72: 2SOD1: 2ATXN2: 1

*********In 1873, however,Charcot reported that ALS was never hereditary, and heused this principle to delineate ALS from spinal muscularThe view that ALS is rarely familial has persisted for several years. However over the last 30 year it has become clear that about 5-10% of ALS cases have strong hereditary componentFor many complex diseases,including alzheimer and PD, familiality ratesare of the order of 5 to 10%.However many of these studies contain flaws, making themUnreliable. The first one in absence of standard definition for FALS**As show in this recent paper from the same groun in which an online questionnaire was sent to cliniciansinvolved in the diagnosis and management of ALS.Respondents were then provided with eight pedigrees andasked whether they would diagnose the proband with FALS..

Although the majority of respondents agreed that having one other affected family member with ALS was sufficient toconstitute a diagnosis of FALS, opinions differed as to whetherthis relative should be at the very least a first-degree relative,a second-degree relative or any relative, no matter how distant.

**The great majority of our FALS cases (40/53, 75.5%) were families with only two affected relatives (Figure 1), a frequency significantly higher than that previously reported in a cohort of FALS families from France and Canada (50 %).9 Different opinions exist as to whether these patients should be classified as FALS. 4 In fact, the possibility exists that two family member can develop ALS from different causes, including genetic factor of couse, but also common environmental factor or simply by chance

that a second person within a kindred is affected by chance if one person already has ALS may not be excluded.9 Traditional Mendelian patterns of inheritance , was recognized in a minority of families.recognized*The possibility exists the two family members may develops ALS from different causes, including genetic factors, common environmental factors or syply by chance.*The great majority of our FALS cases (40/53, 75.5%) were families with only two affected relatives (Figure 1), a frequency significantly higher than that previously reported in a cohort of FALS families from France and Canada (50 %).9 Different opinions exist as to whether these patients should be classified as FALS. 4 In fact, the possibility that a second person within a kindred is affected by chance if one person already has ALS may not be excluded.9 Traditional Mendelian patterns of inheritance , was recognized in a minority of families.recognized*But, on the other hand , under the assumption of polygenic inheritance, thenumber of predicted apparently sporadic cases is high

***The results of this study provide an empirical confirmation of this hypothesis, showing that genetic components due to the currently known major ALS genes exist on a continuum, ranging from fully penetrant phenotypes to apparently sporadic cases. *besides a lower mean age of onset*We have analyzed 480 SAL patients in which genealogies have beenactively investigated,*****Figure 3 | Pleiotropy of genes associated with ALS. Hereditary ALS is not a manygenes, one degenerative syndrome situation. No ALS gene has exclusively beenassociated with an ALS-only motor phenotype. The figure illustrates the reportedrelationships between mutations in different genes and selected clinicalsyndromes. The arrows point to the dominant clinical feature relevant to ALS.Abbreviations: ALS, amyotrophic lateral sclerosis; AOA2, oculomotor apraxiatype!2; FTD, frontotemporal dementia; HSP, hereditary spastic paraparesis; PLS,primary lateral sclerosis; PMA, progressive muscular atrophy, POAG, primary openangle glaucoma; SMA, spinal muscular atrophy.****L144F: Classica*These data suggest that most ALS cases are probably due to oligogenic inheritance, perhapsin combination with environmental factors but monogenic inheritance is also possible*********We have analyzed 480 SAL patients in which genealogies have beenactively investigated,***These data suggest that most ALS cases are probably due to oligogenic inheritance, perhapsin combination with environmental factors but monogenic inheritance is also possible******