PREVALENCE OF CHROMOSOMAL ABNORMALITIES
IN INFERTILE COUPLES IN ROMANIA
Mierla D1,*, Malageanu M1, Tulin R1,2, Albu D1,2
*Corresponding Author: Dana Mierla, PhD, Department of Genetics, Life Memorial Hospital, Grivita Street,
Bucharest, Romania. Tel: +40-72-147-9083. E-mail: dana_mierla@yahoo.com
page: 23
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DISCUSSION
In recent years, more and more studies have
shown an increased incidence of chromosomal abnormalities
in couples with reproductive disorders
[18,19]. Our study was designed to explore the implication
of chromosomal abnormalities in infertility
in men and women. In this study, the incidence of
chromosomal abnormalities in infertile couples is
similar to other studies (2.52% in men and 2.49% in
women). In our study, the autosomal chromosomal
abnormalities consisted of translocations (reciprocal,
Robertsonian) and inversions. Autosomal translocations were found in 1.06% of the infertile patients
(13 patients), 0.68% (eight cases) were reciprocal
translocations between different chromosomes and
0.41% (five men) were Robertsonian translocations.
Within this group, the Robertsonian translocation
[t(13;14)(q10;q10)] is the most frequent translocation
observed in infertile men (0.41%) [8]. Translocations
between group D chromosomes represent
approximately 75.0% of all Robertsonian translocations
[20]. The chromosomal abnormalities play
a determining role in infertility with an incidence
between 10.0 and 15.0% [21]. The incidence of
chromosomal abnormalities in this study is similar
to other studies.
The identified chromosomal abnormalities at the
sex chromosome level are most frequently associated
with male infertility. The prevalence of the Klinefelter
syndrome is 0.6-1.0% in the general population and
up to 10.0% in male infertility [21-23]. In this study,
sex chromosomal abnormalities were found in 14
infertile men (1.14%), five with Klinefelter syndrome
(47,XXY), a syndrome associated with severe disturbance
of the spermatogenesis; two patients with oligozoospermia
presented the karyotype 47,XYY, three
had karyotype 46,XX, two had 46,X,delY(q), one
had an isochromosome of the short arm of chromosome
Y and one patient had the normal chromosomal
mosaicism 47,XXY,22ps+[15]/46,XY,22ps+[5]. Of
the patients with sex chromosomal abnormalities,
3.0% had an infertility from an unknown cause. In
this study, Klinefelter syndrome represents one of the
most frequent causes of male infertility, similar to the
data in the literature [21]. The XYY syndrome is also
a common chromosomal abnormality, most men being
fertile, but there are also studies suggesting an association
with infertility. In this study, we found two
patients with this syndrome and one case of cellular
mosaicism 47,XXY,22ps+[15]/ 46,XY,22ps+[5] [21].
After Klinefelter syndrome, Yq deletions are also
a frequent cause of male infertility [24]. Anomalies of
the Y chromosome have been found in this study in
three (1.0%) patients with infertility of an unknown
cause. Two of these had a deletion of the long arm of
the Y chromosome and one had an isochromosome
of the short arm of chromosome Y. There were also
three reported cases of the XX syndrome in infertile
men, with an incidence of 0.24%. In all these cases,
the mechanism explaining the male phenotype was
translocation of the SRY gene on an X chromosome
[13]. This was observed following the interphase and
metaphase FISH on the cytogenetic preparations.
A high prevalence of chromosomal anomalies
(6.0%) was also observed in patients with a history
of miscarriages. The genetic etiology for miscarriages
includes an unbalanced chromosomal rearrangement
that may be the result of a reciprocal translocation
in one of the partners [25]. Miscarriages represent
an essential cause of female infertility. They can be
caused by chromosomal abnormalities such as reciprocal
or Robertsonian translocations, as well as by
other chromosomal aberrations such as inversions
on chromosome 9. The incidence of chromosomal
abnormalities in the studied group of infertile women
was 2.49%, which is similar to several studies [18]. In
2002, Raziel et al. [13] found an incidence of chromosomal
abnormalities in 14.5% of patients. In our
study, 1.87% of these abnormalities were autosomal
and 0.62% were sex chromosomal abnormalities.
Autosomal abnormalities consisted of translocations
between different groups of chromosomes, inversions
and duplications. Inversions, translocations and duplications
seem to be associated with miscarriages. In
this study group, inversions were identified at chromosomes
1, 5 and 8 in six patients with a history
of miscarriages. The incidence of these pericentric
inversions was 0.62%. In 10 cases, autosomal reciprocal
translocations were identified at chromosomes
1, 3, 4, 9, 10, 13, 15, 16, 18, 19 and 22, with an incidence
of 1.04%, similar to some studies [10]. In this
study group, Robertsonian translocations have been
found at a reduced frequency (0.10%). The incidence
of Robertsonian translocations in female infertility
is higher than in this study (0.69%) [10]. In 2001,
Gekas et al. [10] conducted a study in 1012 infertile
women enrolled in the Intracytoplasmatic Sperm Injection
(ICSI) program. They observed an incidence
of 4.84% of chromosomal abnormalities, where reciprocal
and Robertsonian translocations (0.69%) and
inversions (0.69%), had the highest frequencies [10].
In the group of fertile patients, one case of reciprocal
translocation with the chromosomal karyotype
46,XX,t(13;16) (q33.3;p12.2) was identified. The
childrens’ karyotypes were also determined and it
was found that one of the children presented the same
structural modification as the mother, the other having
a normal karyotype.
The chromosomal abnormalities identified at the
sex chromosome were found in six infertile women (0.62%), three (o.31%) women were diagnosed with
the Turner syndrome in mosaic, one patient (0.10%)
presented karyotype 45,X, another (0.10%) karyotype
46,Xi(Xq), and yet another (0.10%) presented karyotype
46,XY (syndrome 46,XY in women). Turner
syndrome is one of the most frequent chromosomal
abnormalities (1/2500 female newborns). The presence
of the Y chromosome was detected in 6.0% of
the cases through karyotyping and up to 60.0% throug
molecular diagnostics [26]. These patients were also
examined using cytogenetic molecular techniques
(metaphase and interphase FISH), which led to the
observation of the presence of the characteristic signal
for chromosomes X and Y, respectively.
Of the identical chromosomal abnormalities in
the two groups, we point out the structural abnormalities
(1.38% of men and 1.87% of women) and the
numerical abnormalities (1.14% of men and 0.62%
of women). Linking the present chromosomal abnormalities
of the two sexes did not lead to any statistical
significance (p = 0.96).
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