P-10

Autosome-autosome reciprocal translocation: implications in the fertility

Sílvia Pires^I; Natália Oliva Teles^I,II, Nuno Louro^III; Maria da Luz Fonseca e Silva^I

^IUnidade de Citogenética, Centro Genética Médica Doutor Jacinto Magalhães, Centro Hospitalar do Porto - EPE, Porto, Portugal
^IIUnidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto
^IIIServiço de Urologia, Departamento de Cirurgia, Centro Hospitalar do Porto - EPE, Porto, Portugal

Chromosomal abnormalities have been described as important causes of male infertility. Structural rearrangements have been reported as 10 times more frequent among infertile men than in the general population.

The most  common  chromosomal abnormality is Klinefelter’s syndrome, but translocations may also cause reduction in testicular volume and testosterone level, which may impact spermatogenesis, resulting in oligozoospermia or azoospermia and thus male infertility. The involvement of acrocentric chromosomes and the presence of translocation breakpointsincloseproximitytothecentromereareassociated with the most destructive effects on spermatogenesis.

It has been suggested in some publications that the most likely reason for the development of azoospermia in patients with reciprocal translocations is  a  very  high  proportion of an association between XY bivalents and quadrivalent formations in prophase I; the instability in chromosome segregation during consecutive cell divisions might be a contributing factor inducing spermatogenic disruption.

The authors present a male patient, aged 41, with azoospermia and reduced testicular volume, without family history of infertility.

The karyotype revealed an autosome-autosome reciprocal translocation: 46,XY,t(20;22)(q11.21;q11.21). Chromosomal analysis has become increasingly important for characterizing possible causes of human infertility, and has shown that male infertility might be associated with autosomal chromosome abnormalities. Infertile men who have chromosomal abnormalities such as translocations but normal phenotypes have shown that these translocations may have a devastating impact on spermatogenesis during meiotic division. In addition, detailed meiotic analysis may be recommended for each translocation, to obtain better diagnosis, prognosis and genetic counselling to the patient.

The authors will establish the relationship between male infertility and chromosomal translocations and compare the findings of this patient with similar cases described in the literature.