Meiotic defects and decreased expression of genes located around the chromosomal breakpoint in the testis of a patient with a novel 46,X,t(Y;1)(p11.3;p31) translocation

Chromosome 1q21 translocation and spermatogenesis failure: Two case reports and review of the literature

RATIONALE

For the carriers of chromosome reciprocal translocation, the reason why some are fertile and others are infertile remains unclear. Here, we describe 2 patients who are carriers of chromosome 1q21 translocation with azoospermia.

PATIENT CONCERNS

A 29-year-old male and a 33-year-old male presented at the clinic with a diagnosis of infertility.

DIAGNOSIS

Both patients with azoospermia were diagnosed with Routine semen analysis, cytogenetic diagnosis and detection of serum reproductive hormones. The karyotype results of 2 patients were 46,XY,t(1;17)(q21;q23) and 46,XY,t(1;10)(q21;p12), respectively.

INTERVENTIONS

After genetic counseling and informed consent, 1 patient (Case 2) chose microsopic testicular sperm extraction (micro-TESE).

OUTCOMES

After micro-TESE, no sperm was found for the patient. Finally, both patients chose clinical treatment through artificial insemination with donor sperm.

LESSONS

These outcomes suggest that breakpoint at 1q21 should be paid attention by physician in genetic counseling, may harbor some genes associated with spermatogenesis, and deserves further be studied on the function of related genes.

Meiotic Synapsis and Gene Expression Altered by a Balanced Y-Autosome Reciprocal Translocation in an Azoospermic Pig

Meiotic sex chromosome silencing (MSCS) has been argued as a prerequisite for normal meiotic cell division progression during the synaptic prophase I stage. Furthermore, irregular asynapsis of autosomal axes at meiosis may be encompassing the lack of transcriptional activity normally observed for the X and Y sex chromosomes. Therefore, any chromosomal rearrangement compromising the normal mechanism of MSCS and/or the contrary, the normal meiotic transcriptional activity of autosomal chromosomes, may be observed as a meiotic and concomitant spermatogenesis arrest. Previously, we have described a Y-autosome translocation t(Y;13)(p1.3;q3.3) in an azoospermic boar. Its chromosome synapsis behavior by synaptonemal complex immunostaining and FISH analyses is documented here. Histone γH2AX protein foci appeared to be located at unsynapsed chromosomal segments (e.g., X chromosome univalents or unpaired multivalent segments), although interestingly a high proportion of primary spermatocytes showed full paired synaptonemal complex-multivalent configurations which were devoid of a γH2AX focus signal, indicating meiotic chromosome silencing. RT-qPCR analysis of testicular expression showed downregulation of 3 SSC13 genes (MLH1, SOX2, UBE2B) and upregulation of SSCY genes (ZFY, SRY). The irregularity of the normal transcription pattern in case of these genes with proven roles in the testis is in agreement with the cytological observations and could contribute to the observed phenotype.