* CHROMOSOME SEGREGATION AND INTERCHROMOSOMAL EFFECT IN HUMAN EMBRYOS FROM CARRIERS OF CHROMOSOMAL REARRANGEMENT. MULTICENTRAL STUDY ulia Loginova he International Centre of eproductive Medicine (MCRM) ussian Federation The 5th Congress of the Asia Pacific Initiative on Reproduction Brisbane, Australia, 4 - 6 April 2014.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
* CHROMOSOME SEGREGATION AND INTERCHROMOSOMAL EFFECT IN
HUMAN EMBRYOS FROM CARRIERS OF CHROMOSOMAL REARRANGEMENT.
MULTICENTRAL STUDY
Julia LoginovaThe International Centre of Reproductive Medicine (MCRM)Russian Federation
The 5th Congress of the Asia Pacific Initiative on ReproductionBrisbane, Australia, 4 - 6 April 2014.
couples with recurrent miscarriage (RM) - 4.7- 9.2 %
infertile males requiring ICSI (severe male factor) - 2-3.2%
The incidence of balanced chromosomal rearrangement
Birth of children with unbalanced karyotype 1-17%
Stillbirth / infant death 5-8%
Miscarriage 20-30%
Unbalance karyotypeRevealed by amniocentesis 14-28%(second trimester)
Effect of the parental balance chromosomal
rearrangement for offspring:
balanced chromosomal rearrangementChromosomal segregation during gametogenesis may lead to production of gametes with gains and losses of genetic material -
theoretically - 50%, empiric date – large variability 0? - 100? %
Rate of balanced and unbalanced gametes depends on: • Type of rearrangement• Involved chromosomes • Breakpoints • Carrier's sex• Genetic background • IVF - Environment
OBJECTIVES: analysis of chromosomal segregation patterns and estimation an inter-chromosomal effect (ICE) in embryos obtained from male and female rearrangement carriers (Robertsonian translocations, reciprocal translocations, pericentric inversions).
understanding the segregation mechanisms of the chromosomes involved and not involved in the
rearrangements GENETIC COUNSELING: estimation the risks of pregnancy loss and birth defects in the offspring
IVF:prediction the PGD cycles outcome
IVF / ICSI
FISH
Biopsy: Day 3 (95% cases);Day 5 (5% cases)
ET fresh – 90%, frozen 10%
genetic counseling
Testing of the specific FISH probes on the metaphase chromosomes from the couples (carrier and his/her partner)
Methods:
Day 5Day 4
FISH: 3 - 7 re-hybridization steps (depending on the fixed nuclei quality)3 - 8 markers for rearrangement chromosomes +PGS for 7-12 chromosomes not involved in rearrangement (1-3 markers for every tested chromosomeFISH markers: locus-specific probes, subtelomeric/centromeric probes
patients:45,XX,der(15;22)(q10;10)46,XY
15ceno, 15qtelo ,
22q11o15p11.2o, 15ceno, 14q11.2o+o , 22q11o
MultyPB, CEPXo+o,CEPYo+o
18q21o+o, 16qtelo , 21q22 o
18q21o+o, 22q11o , 21q22 o
FISH steps: 1st 2nd 3rd 4th
31
3431
136 7
13
Reciprocal (REC)
Robertsonian (ROB)
pericentric inversion (INV)
other
PGD cycles (n=125) Embryos (n=907)
Other rearrangements:46,XY,t(1;8)(q32.1;q24,1),der(15)t(Y;15)(q12;q10)46,XY,der(15)t(Y;15)(q12;p11.2)45,X[25]/46,X,r(X)[5]46,X,r(Y)[30]/45,X[20]
233
249242
8827 47
1 20
♀
♂
♀ ♂
♀
♂
♂♀
♂
♂
♂
♂♀
♀
♀
♀
- balansed, euploid
- balansed, aneuploid
- unbalanced, euploid
- unbalansed, aneuploid
- other unbalans
carriers ♀
REC (n=451)
carriers ♂
ROB (n=330)
INV (n= 72)
14%
6+22=28%
14+26=40%
31+20=51%
Segregation patterns according rearrangement type and carrier’s sex
14% 4%
44%
32%
7%17%
6%
45%
22%
10%
28%
14%
24%
22%
12%
40%
12%11%
26%
10%
37%
22%
15%
19%
7%
36%
31%
20%
13%
28%
37%
17%
40%
36%
**
*
4+32=36%
14+22=36%
22+19=41%
REC segregation pattern according to the carrier’s sex
carrier ♂ embryos n= 225carrier ♀ embryos n = 220
alternate (n/b)
adja
cent
-1 pl
oidy
ab
norm
aliti
esadja
cent
-2
reco
mbi
nan
ts
mosaic
chaotic3:1 4:0
0
5
10
15
20
25
%ns ns
6.1% 7.7%
REC segregation pattern according to chromosome types (acrocentric chromosome involvement) and to the carrier’s sex embryos n= 463
n/b adj1 adj2 3:1 4:0 recomb ploidy mos chaotic abnorm.
0
5
10
15
20
25
30 *% ♂♀
with
acr
o
with
out a
cro
n=103 n=140
n=79 n=141
ns*
9.5%
mosaic
chaotic
ROB segregation pattern according to sex of the carrier
Carriers of different chromosomal rearrangements have different reproductive genetic risk:
- the carriers of reciprocal translocations regardless of their gender have a higher risk of aneuploid embryos than other carriers.
- the male carriers of Robertsonian translocations have lower risk of aneuploid embryos, than female. The possible explanation is specific chromosome segregation in meiosis and/or selection during subsequent spermatogenesis stages
There is no significant influence of gender on the rearranged chromosomes segregation pattern for reciprocal and Robertsonian translocations carriers
For reciprocal translocations the modes of segregation pattern depend on the involvement of acrocentric chromosomes
Conclusion:
Conclusion:
ICE regardless of gender is more evident if the maternal age is less than 35. This suggests that the embryonic aneuploidy in older women depends more on the woman’s age than the rearrangement itself
In male carriers the embryonic aneuploidy rate caused by ICE depends on the rearrangement type
The strongest ICE was detected in both gender carriers of Robertsonian translocations and pericentric inversions.
IVF units:
Russian LatviaFederationSt.Petersburg: Riga: MCRM, Jusu ArstiPrivatklinika Mother and Child