Unique (Y;13) translocation in a male with oligozoospermia: cytogenetic and molecular studies

Abstract

The incidence of Y/autosome translocations is low. Whereas involvement of non-acrocentric chromosomes often leads to infertility, cases related with acrocentric chromosomes are usually familial with no or minimal effect on fertility. A de novo (Yp/13p) translocation was found in a 32-year-old male referred for severe oligozoospermia. Conventional cytogenetic procedures (GTG, CBG and NOR banding) and molecular cytogenetic techniques (Fluorescence In Situ Hybridization, FISH) were performed on high-resolution chromosomes obtained after peripheral blood lymphocyte culture as also on interphase nuclei of spermatogenic cells from semen samples. Screening of AZF microdeletions in the Yq11.2 region known to be involved with spermatogenesis defects was also performed. GTG banding showed a (Yp/13p) translocation in all scored metaphases. CBG and NOR staining of the derivative chromosome revealed the maintenance of Yq heterochromatin and of the 13p NOR region. FISH with centromeric Y and 13/21 probes, SRY specific probe and X/Y (p and q arms) sub-telomeric probes gave the expected number/location of fluorescent signals. Hybridisation with a pan-telomeric repeat (TTAGGG) probe showed an absence of the telomeric sequences at the fusion point of the rearranged chromosome. FISH analysis with probes to chromosomes X, Y, 13 and 18 showed an abnormal segregation of the translocated chromosome during meiosis I, which explains that only 13.6% of the secondary spermatocytes were normal. Most of these became arrested, as after meiosis II the large majority of the round spermatids were normal (70%), as were in consequence most of the sperm (85.1%). Multiplex-PCR confirmed the intactness of the SRY region and showed absence of AZF microdeletions. We report a novel de novo (Yp;13p) translocation characterised by loss of the 13p and Yp telomeres. Meiotic studies using FISH demonstrated meiosis I chromosome unpairing and mal segregation that justifies the severe oligozoospermia. Although most sperm have a normal chromosomal constitution, preimplantation genetic diagnosis should be considered an option for this patient.

Somatic chromosomal abnormalities in infertile men and women

“…The frequency of Y-autosome translocations in the general population is approximately 1 in 2000 (Alves et al, 2002). Altogether 13 reciprocal Y-autosome translocations were described in the various surveys (Table 2), distributed among the different groups with a preponderance in the oligozoospermic group (five cases, 0.2 %) and in the ICSI group (six cases, 0.09 %).…”

Comprehensive Genomic Study in Patients with Idiopathic Azoospermia and Oligoasthenoteratozoospermia

“…the involvement of the Y chromosome in translocation with autosome is reported to have a frequency of 1:2000 (10,20,25). Usualy they are between Y and another acrocentric chromosome; Y/non-acrocentric autosome translocation is quite rare (1). in another patient from our study we revealed pericentric inversion of chromosome 9. this is considered to be one of the most frequent polymorphisms of human chromosomes, occurring in 0.9 % to 4 % of the general population (18).…”

An infertile 45,X male with a SRY-bearing chromosome 13: a clinical case report and literature review

“…To date, five cases of monosomy X males with an SRYbearing chromosome 13 have been reported (Table 1) [6][7][8][9][10]. In all the latter cases, the presence of Y chromosome material on chromosome 13 was visible at the resolution of G-band analysis.…”