Molecular cytogenetic studies of a male carrier with a unique (Y;14) translocation: Case report

Abstract Background Chromosome translocation is a genetic factor associated with male infertility. However, cases of Y chromosome/autosome translocation are rare. Individuals with translocation between the Y chromosome and an autosome have a variety of different clinical phenotypes. There is a need for further study of molecular cytogenetic feature of those with Y chromosome translocation. Methods We reported that an apparently healthy 31‐year‐old man, 168 cm tall and weighing 65 kg, had a 2‐year history of primary infertility after marriage. Clinical diagnostic techniques included semen analysis, hormone measurements, cytogenetic analysis, fluorescence in situ hybridization (FISH), and high‐throughput multiplex ligation‐dependent probe amplification semiconductor sequencing. Detailed genetic counseling was provided to the patient. Intracytoplasmic sperm injection treatment combined with preimplantation genetic diagnosis was chosen with the aim of achieving a successful pregnancy. Results Semen analysis revealed cryptozoospermia. Hormone levels were within the normal limits. Sequencing results indicated the presence of the sex‐determining region on Yp, and AZFa, AZFb, and AZFc regions on Yq. The patient's karyotype was 45,X,psu,dic(Y;14)(p11.3;q11.2), which was confirmed by cytogenetic analysis and FISH. Conclusion This study reports a case of cryptozoospermia in a male patient with a Y;14 chromosomal translocation. When clinical karyotyping has revealed potential Y chromosome abnormality, FISH or molecular detection should be further performed to facilitate identification of the chromosomal breakpoint.

offspring without phenotypic repercussions. 6 A review of those with Y-autosome translocation indicated that most translocations lead to azoospermia or oligozoospermia. 2 These conditions may be related to breakpoints, balanced, or unbalanced chromosomal changes involved in translocation. 7,8 Previous studies were mainly based on G-banding analysis, 2 which could not determine detailed structures. 5 Therefore, some unique chromosomal abnormalities require further identification of breakpoints or detailed structures. Here, we describe a male carrier with a unique (Y; 14) translocation, including his molecular cytogenetic characteristics.

| MATERIAL S AND ME THODS
This study was approved by the Ethics Committee of the First Hospital of Jilin University (No. 2019-230). Written informed consent was obtained from the patient for publication of this case report.

| Semen analysis
Semen samples were collected by masturbation after abstinence of 3-5 days. After these samples had been completely liquefied at 37°C, semen analysis was performed in accordance with the World Health Organization's standard protocol. 9 If no sperm were found, semen samples were centrifuged (3000 g for 15 minutes) and the sediment was then reexamined. The patient was confirmed to have cryptozoospermia by the analysis of two centrifuged semen samples at an interval of 1 month.

| Cytogenetic analysis
After the provision of informed consent, peripheral blood was collected from the patient and lymphocytes were cultured for 72 hours in appropriate culture medium (Cell Preservation Medium; Sinochrome). Karyotype analysis was performed using G-band staining in accordance with standard cytogenetic procedures. Twenty metaphases were analyzed for this sample.

| Molecular analysis
To analyze the frequency of Y chromosome microdeletions, human blood samples were collected from the patient, from which genomic DNA was extracted. Semiconductor sequencing was performed in accordance with our previous study. 10 Markers included 36 sequencetagged sites, the sex-determining region on the Y chromosome (SRY), and zinc finger proteins, namely X-linked and Y-linked zinc finger proteins used as internal controls, as described in our previous study. 5

| Fluorescence in situ hybridization (FISH) analysis
FISH was performed to detect the sex-determining region on the Y chromosome (SRY) and the long arm of the Y chromosome (Yq12). The detailed operating protocol was followed as in our previous study. 11

| D ISCUSS I ON
Chromosome translocation is one of the genetic factors known to be associated with male infertility. 12 However, cases of Y chromosome/ autosome translocation are rare. 13  Through assisted treatment of intracytoplasmic sperm injection treatment, the patient gave birth to his own offspring. These results suggest that the detailed diagnosis and assisted reproductive technology should be recommended for male carriers with Y chromosome abnormalities.
A limitation of this study is the lack of detection of the origin of this chromosomal abnormality because the patient's parents refused to undergo chromosomal analysis.

F I G U R E 1
The karyotype of the case was found to involve 45,X,t(Y;14) F I G U R E 2 Metaphase-FISH results of an alphoid probe for SRY and Yq1 probe 2: the red arrow indicates the SRY signal, the green arrow Yq12, and the blue arrow the X centromere signal

| CON CLUS IONS
We report a case of cryptozoospermia in a male patient with a Y;14 chromosomal translocation. When clinical karyotyping has revealed potential Y chromosome abnormality, FISH or molecular detection should be further performed to facilitate identification of the chromosomal breakpoint.

ACK N OWLED G M ENTS
We thank Liwen Bianji, Edanz Group China (www.liwen bianji.cn/ac), for editing the English text of a draft of this manuscript.