POLYPLOIDY PHENOMENON AS A CAUSE OF EARLY MISCARRIAGES IN ABORTION MATERIALS
Yildirim ME, Karakus S, Kurtulgan HK, Ozer L, Celik SB
*Corresponding Author: Malik Ejder Yildirim, Associate Professor. Department of Medical Genetics, Faculty of Medicine, Sivas Cumhuriyet University, 58104 Sivas, Turkey. Phone: 03462581085, Email: nemalik2002@gmail.com
page: 5
|
|
DISCUSSION
Although various problems from immune dysregulation
to thrombophilia have been shown to play a role in
the etiology of miscarriages, it is stated that most of the
abortions are caused by genetic abnormalities [17]. Various
chromosomal changes are particularly predominant in
cases of abortion. Most chromosomal disorders are sporadic
and have little risk of recurrence, but their analysis is
important for couples and has a prognostic value in terms
of the next pregnancy [18]. Chromosomal problems in the
form of aneuploidy (trisomy-monosomy) and polyploidy
(triploidy-tetraploidy) are determining factors in at least
50% of first trimester abortions, 25% of second, and 11%
of third trimester miscarriages [19]. Cytogenetic analysis
of conception products (POCs) can be done to identify
the genetic cause of miscarriages, to predict recurrence
risk, and to provide important information for genetic
counseling and reproductive planning. This procedure,
however, has some limitations due to a risk of culture
failure, maternal cell contamination, suboptimal chromosome
preparation etc. [20]. It is important to carry out
cytogenetic analysis in terms of Preimplantation Genetic
Screening (PGS) in IVF clinics in order to suggest suitable
management and/or treatment approaches in recurrent miscarriage
[21]. Conventional G-banding karyotyping is used
as a gold standard procedure to determine chromosomal
aneuploidy and some other variations [22].
Along with polyploidy, aneuploidy (trisomy or monosomy)
was also prominent as a significant cause of spontaneous
abortions in our study. In addition to chromosomal
abnormalities (triploidy, tetraploidy, trisomy, monosomy,
translocation, etc.), we found some chromosomal variations
(heterochromatin and satellite increments, inversion
9) in abortion materials. The relationship of these variations
with miscarriage is is not clear.
Polyploidy is a fatal cytogenetic anomaly that often
results in pregnancy loss. [23]. Russo et al. stated that most
chromosomal abnormalities in early spontaneous abortion
are aneuploidies [24], while Brancati et al. claimed that
triploidy is the most common chromosome abnormality
in first trimester spontaneous abortions [25]. On the other
hand, in a study by Carson et al., triploidy was declared
as the third most common cause of pregnancy loss [26].
Polyploidy cases can be found at a high rate in spontaneous
abortions, and they are expected to be lethal with multiple
congenital defects. Triploidy is a numerical chromosomal
aberration characterized by the presence of an extra haploid
chromosome set and may occur in approximately 17%
of spontaneous abortions in first trimester [27]. A third
chromosome set in this condition may originate either
from the mother or the father at the time of fertilization.
Triploid pregnancies often result in early miscarriage or
infants die within the first days of life. Some cases who
have a mosaic form may survive with various problems.
On the other hand, Dória et al reported that approximately
1,3% of first trimester miscarriages are true tetraploid [28].
Tetraploidy is very rare condition in live-born infants and it
is usually detected in mosaic form with various anomalies
[29]. Complete tetraploidy can often be found in spontaneous
abortions [30].
Lee et al. identified single autosomal trisomy (71%)
as the most common genetic defect in miscarriage. In this
study, certain rates of polyploidy (16.1%), multiple aneuploidy
(9.7%) and monosomy X (3.2%) were present. The
rate of genetic abnormalities was also high in this research
(49.2%) [31]. Similarly, Gug et al. found autosomal trisomies
as the most common chromosomal abnormality in
miscarriages (56.4%). In this study, the rate of polyploidy
was 16.2%, monosomy 16.2%, and structural abnormalities
11.5% [32]. However, Lathi et al. state that the most common
numerical chromosome problem identified in first trimester
spontaneous abortions is monosomy X, followed by
trisomy 16 and other chromosomal disorders, such as triploidy
and tetraploidy are responsible for about 8% of miscarriages
with numeric chromosomal defects [33]. Oliveira
et al. suggested that a case of repeated triploid pregnancies
in the same woman, from different fathers strongly point to
recurrent triploidies with maternal origin, and therefore genetic
predisposition should be considered [34]. We detected
a high rate of polyploidy in spontaneous abortion materials.
A polyploid case has three or more times the haploid number
of chromosomes and it is not clear why polyploidy occurs
in pregnancy. Polyploidy does not appear to be a condition
related to maternal age [35]. However, high paternal age
may be associated with the occurrence of polyploidy, particularly
triploidy. A possible dyspermia may be the source
of an extra set of paternal chromosomes. The prevalence of
paternal (diandric) triploidy varies between 20% and 85%
in various studies and the vast majority of them are lost in
the first trimester of pregnancy [36]. Most triploidies may
have paternal origin, and diandric triploidy can often be
diagnosed as partial hydatidiform moles with abnormal
placentas characterized by trophoblastic proliferation [37].
Although diandric triploids are often caused by dispermy,
data regarding the effect of paternal age on the incidence
of triploidy are still lacking [38]. We encountered a higher
average paternal age in polyploidy cases than in abortions
with normal karyotype. Most of the polyploidies (81.8%)
were triploidy in our study (Figure 2). However, this issue
is not clear due to the relatively small number of cases in
our study. Therefore, the possible cause of polyploidy or
triploidy should be investigated in larger groups including
many abortion samples and thus more triploidy cases.
In conclusion, we investigated karyotype abnormalities
in spontaneous abortion materials in this study and
detected various structural and numerical chromosomal
anomalies and some variations. Routine studies and analyses
to be carried out in this manner are important for
subsequent pregnancies. The most common abnormality
we observed was polyploidy (triploidy and tetraploidy).
It was followed by trisomy, translocation and monosomy.
In this context, we can say that polyploidy is involved in
the etiology of a significant portion of miscarriage cases.
In addition, more comprehensive study groups should be
screened to evaluate clearly, whether paternal age contributes
to polyploidies, especially triploidies.
Declaration of Interest. The authors report no conflicts
of interest. The authors alone are responsible for the
content and writing of this article.
|
|
|
|
 |
Number 27
VOL. 27 (2), 2024 |
Number 27
VOL. 27 (1), 2024 |
Number 26
Number 26 VOL. 26(2), 2023 All in one |
Number 26
VOL. 26(2), 2023 |
Number 26
VOL. 26, 2023 Supplement |
Number 26
VOL. 26(1), 2023 |
Number 25
VOL. 25(2), 2022 |
Number 25
VOL. 25 (1), 2022 |
Number 24
VOL. 24(2), 2021 |
Number 24
VOL. 24(1), 2021 |
Number 23
VOL. 23(2), 2020 |
Number 22
VOL. 22(2), 2019 |
Number 22
VOL. 22(1), 2019 |
Number 22
VOL. 22, 2019 Supplement |
Number 21
VOL. 21(2), 2018 |
Number 21
VOL. 21 (1), 2018 |
Number 21
VOL. 21, 2018 Supplement |
Number 20
VOL. 20 (2), 2017 |
Number 20
VOL. 20 (1), 2017 |
Number 19
VOL. 19 (2), 2016 |
Number 19
VOL. 19 (1), 2016 |
Number 18
VOL. 18 (2), 2015 |
Number 18
VOL. 18 (1), 2015 |
Number 17
VOL. 17 (2), 2014 |
Number 17
VOL. 17 (1), 2014 |
Number 16
VOL. 16 (2), 2013 |
Number 16
VOL. 16 (1), 2013 |
Number 15
VOL. 15 (2), 2012 |
Number 15
VOL. 15, 2012 Supplement |
Number 15
Vol. 15 (1), 2012 |
Number 14
14 - Vol. 14 (2), 2011 |
Number 14
The 9th Balkan Congress of Medical Genetics |
Number 14
14 - Vol. 14 (1), 2011 |
Number 13
Vol. 13 (2), 2010 |
Number 13
Vol.13 (1), 2010 |
Number 12
Vol.12 (2), 2009 |
Number 12
Vol.12 (1), 2009 |
Number 11
Vol.11 (2),2008 |
Number 11
Vol.11 (1),2008 |
Number 10
Vol.10 (2), 2007 |
Number 10
10 (1),2007 |
Number 9
1&2, 2006 |
Number 9
3&4, 2006 |
Number 8
1&2, 2005 |
Number 8
3&4, 2004 |
Number 7
1&2, 2004 |
Number 6
3&4, 2003 |
Number 6
1&2, 2003 |
Number 5
3&4, 2002 |
Number 5
1&2, 2002 |
Number 4
Vol.3 (4), 2000 |
Number 4
Vol.2 (4), 1999 |
Number 4
Vol.1 (4), 1998 |
Number 4
3&4, 2001 |
Number 4
1&2, 2001 |
Number 3
Vol.3 (3), 2000 |
Number 3
Vol.2 (3), 1999 |
Number 3
Vol.1 (3), 1998 |
Number 2
Vol.3(2), 2000 |
Number 2
Vol.1 (2), 1998 |
Number 2
Vol.2 (2), 1999 |
Number 1
Vol.3 (1), 2000 |
Number 1
Vol.2 (1), 1999 |
Number 1
Vol.1 (1), 1998 |
|
|
