46,XX, der(15),t(Y;15)(q12;p11) karyotype in an azoospermic male

Abstract

We report on a Yq/15p translocation in a 23-year-old infertile male referred for Klinefelter Syndrome testing, who had azoospermia and bilateral small testes. Hormonal studies revealed hypergonadotropic hypogonadism. Conventional cytogenetic procedures giemsa trypsin giemsa (GTG) and high resolution banding (HRB) and molecular cytogenetic techniques Fluorescence In Situ Hybridization (FISH) performed on high-resolution lymphocyte chromosomes revealed the karyotype 46,XX, t(Y;15)(q12;p11). SRY-gene was confirmed to be present by classical Polymerase Chain Reaction (PCR) methods. His father carried de novo derivative chromosome 15 [45,X, t(Y;15)(q12;p11)] and was fertile; the karyotype of the father using G-band technique confirmed a reciprocal balanced translocation between chromosome Y and 15. In the proband, the der (15) has been inherited from the father because the mother had a normal karyotype (46,XX). In the proband, the der (15) could have produced genetic imbalance leading to unbalanced robertson translocation between chromosome Y and 15, which might have resulted in azoospermia and infertility in the proband. The paternal translocation might have lead to formation of imbalanced ova, which might be resulted infertility in the proband. Sister's karyotypes was normal (46,XX) while his brother was not analyzed.

Keywords: 46; Fluorescence In Situ Hybridization; XX male; Yq;15p translocation; azoospermia; infertility.

Figure 1

In G banded karyotype, the der(15) (arrow) in the father and our patient were seen. His mother and sister have normal karyotype. His brother karyotype could not determined and he did not accept giving blood sample for detecting karyotype

Figure 2

Spectrum Aqua filter set fluorhopore-labeled alpha satellite DNA 18 probe, Spectrum Green probelabeled alpha satellite DNA X probe and Spectrum Orange probe-labeled alpha satellite DNA Y probe. We used DAPI/Orange/Green Filter set for enumeration to CEP X Spectrum Green/CEP Y Spectrum Orange. Fluorescent in situ hybridization (FISH) result showed that there were two chromosomes X and one Y chromosomes

Figure 3

Fluorescence in situ hybridization on metaphase chromosomes using CEP X/SRY specific probes. Arrows indicate two X chromosome centromeric signals (blue) and one SRY specific signal (red) on the ends of chromosome 15. Fluorescent in situ hybridization (FISH) shows fluorescence illumination of the long arm of the Y chromosome and the short arm (q11 of the Y chromosome) of the derivative chromosome 15. The images were obtained separately and were captured. FISH result showed that there were two chromosomes X and one derived chromosome 15 contained Yq11.1 signals in peripheral blood lymphocyte from the patient.