Male infertility affects at least 180 million people worldwide [2]. Given the substantial number of genes involved in spermatogenesis, idiopathic infertility accounts for about 50% of cases in males. As such, the current study was conducted to identify the most significant genes affecting male infertility to establish biomarkers for this condition. We initially searched the STRING database for PPIs in male infertility. Thereafter, we searched Cytoscape using MCODE and CytoHubba applications, through which we identified the three most significant genes that could potentially as indicators of male infertility biomarkers, namely, TEX11, SPO11, and SYCP3.

TEX11 (Human testis express) is a meiosis-specific X-linked gene that plays a role in the spermatogenesis process. According to research by Bellil H, et al. [22] TEX11 (at Xq13.1), is the gene most commonly linked to azoospermia. The cytoplasm and nucleus of type B spermatogonia in mice contain the TEX11 protein, which most abundant in zygotene spermatocytes and at least abundant late pachytene spermatocytes, thus indicating an important role for TEX11 in the initial phases of the formation of germ cell.

Based on research by Yang, et al. [23, 24] loss of the TEX11 gene will cause meiosis failure in men, thus explaining the role of the encoded protein in spermatogenesis. Human infertility results from spermatocytes undergoing apoptosis at the pachytene stage and surviving cells displaying chromosome nondisjunction during the first miotic division. He also discovered that altering this allele genetically can be a tactic to ascertain the in vivo effect of human TEX11 mutations. Yu et al. [25] claims that TEX11 prevents ERβ from binding to a protein that interacts with the transcription factor associated with hematopoietic pre-B cell leukemia, hence suppressing the phosphorylation of the AKT and ERK signaling pathways.

In two brothers who had azoospermia, Sha [26] found a novel mutation in exon 29 TEX11 (2653G‒T; GenBank accession number, NM_031276). First, whole-exome sequencing (WES) was used to confirm this mutation. Then, specific exon 29 was amplified and sequenced. The same missense exonic mutation (W856C) was present in the two brothers but not in their mother, carried. According to the testicular biopsy's histological study, meiosis had stopped, and the seminiferous tubules had neither mature spermatozoa nor post-meiotic spherical spermatids. Sertoli cells and interstitial cells did not express TEX11; spermatogonia expressed it strongly, whereas spermatocyte expressed it weakly.

SPO11 is a 13 exons gene that is found on chromosome 20 (20q13 0.2–13.3) in human and is involved in the processes of meiosis and spermatogenesis, where in humans this gene is located with. Research regarding Spo11 with male infertility is still limited. A case–control of SNP (rs28368082) in exon 7 of the SPO11 gene and its potential correlation with male infertility was carried out in three Iranian provinces by Galkhani et al. in 2014. This study showed that polymorphisms in the SPO11 gene may be linked to azoospermia and oligospermia susceptibility in three Iranian provinces [27]. This contrasts with research conducted by Karimian [28], on 200 samples with 100 healthy men and 100 infertile men, the findings demonstrated that while Spo11-C631T can damage mRNA and protein, it does not raised the risk of male infertility. According to a meta-analysis study by Ren SZ, et al., 2017, the SPO11 C631T gene polymorphism may be a hereditary factor that can lead to male infertility [29].

SYCP3 (synaptonemal complex protein 3) is a synapse-associated DNA-binding protein involved in germ cell meiosis, located on chromosome 12 (12q23), that is a testicular specificity to the expression. SYCP3 contains two coil-over domains and encodes 236 amino acids. A mutation analysis was performed on all coding regions and adjacent introns in 19 patients with azoospermia, which had been histologically shown to be caused by anomalies in meiosis. The azoospermia gene, SYCP3, was discovered by Miyamoto on the human chromosome, outside the AZF region of the Y chromosome. SYCP3 mutation cause azoospermia in males by arresting meiosis [30]. On the other hand, research on Caucasian-Spanish or Maghribians individuals without Y chromosomal loss revealed no abnormalities in the SYCP3 gene’s coding region in samples of azoospermia or severe oligozoospermia infertile male patients [31].

The aforementioned research suggests that the TEX11, SPO11 and SYCP3 genes play a role in meiosis and spermatogenesis. This is consistent with the results of our analysis, which found that these three genes play a role in male infertility. Therefore, we suppose that such genes can become biomarkers for patients with male infertility.