The genetic basis of nonobstructive azoospermia is unknown in the majority of infertile men. We performed array comparative genomic hybridization testing in blood samples obtained from 15 patients with azoospermia, and we performed mutation screening by means of direct Sanger sequencing of the testis-expressed 11 gene (TEX11) open reading frame in blood and semen samples obtained from 289 patients with azoospermia and 384 controls. We identified a 99-kb hemizygous loss on chromosome Xq13.2 that involved three TEX11 exons. This loss, which was identical in 2 patients with azoospermia, predicts a deletion of 79 amino acids within the meiosis-specific sporulation domain SPO22. Our subsequent mutation screening showed five novel TEX11 mutations: three splicing mutations and two missense mutations. These mutations, which occurred in 7 of 289 men with azoospermia (2.4%), were absent in 384 controls with normal sperm concentrations (P=0.003). Notably, five of those TEX11 mutations were detected in 33 patients (15%) with azoospermia who received a diagnosis of azoospermia with meiotic arrest. Meiotic arrest in these patients resembled the phenotype of Tex11-deficient male mice. Immunohistochemical analysis showed specific cytoplasmic TEX11 expression in late spermatocytes, as well as in round and elongated spermatids, in normal human testes. In contrast, testes of patients who had azoospermia with TEX11 mutations had meiotic arrest and lacked TEX11 expression. In our study, hemizygous TEX11 mutations were a common cause of meiotic arrest and azoospermia in infertile men. (Funded by the National Institutes of Health and others.)

Background: Genetic causes that lead to spermatogenetic failure in patients with nonobstructive azoospermia (NOA) have not been yet completely established.Objective: To identify low‐frequency NOA‐associated single nucleotide variants (SNVs) using whole‐genome sequencing (WGS).Materials and methods: Men with various types of NOA (n= 39), including samples that had been previously tested with whole‐exome sequencing (WES;n= 6) and did not result in diagnostic conclusions. Variants were annotated using the Ensembl Variant Effect Predictor, utilizing frequencies from GnomAD and other databases to provide clinically relevant information (ClinVar), conservation scores (phyloP), and effect predictions (i.e., MutationTaster). Structural protein modeling was also performed.Results: Using WGS, we revealed potential NOA‐associated SNVs, such as:TKTL1, IGSF1, ZFPM2, VCX3A(novel disease causing variants),ESX1, TEX13A, TEX14, DNAH1, FANCM, QRICH2, FSIP2, USP9Y, PMFBP1, MEI1, PIWIL1, WDR66, ZFX, KCND1, KIAA1210, DHRSX, ZMYM3, FAM47C, FANCB, FAM50B(genes previously known to be associated with infertility) andALG13, BEND2, BRWD3, DDX53, TAF4, FAM47B, FAM9B, FAM9C, MAGEB6, MAP3K15, RBMXL3, SSX3andFMR1NBgenes, which may be involved in spermatogenesis.Discussion and conclusion: In this study, we identified novel potential candidate NOA‐associated genes in 29 individuals out of 39 azoospermic males. Note that in 5 out of 6 patients subjected previously to WES analysis, which did not disclose potentially causative variants, the WGS analysis was successful with NOA‐associated gene findings.

Male infertility might be clearly associated with aberrant DNA methylation patterns in human spermatozoa. An association between oxidative stress and the global methylation status of the sperm genome has also been suggested. The aim of the present study was to determine whether the global sperm DNA methylation status was affected in the spermatozoa of carriers of chromosome structural aberrations. The relationships between the 5-methylcytosine (m5C) levels in spermatozoa and chromatin integrity status were evaluated. The study patients comprised male carriers of chromosome structural aberrations with reproductive failure (n = 24), and the controls comprised normozoospermic sperm volunteers (n = 23). The global m5C level was measured using thin-layer chromatography (TLC) and immunofluorescence (IF) techniques. The sperm chromatin integrity was assessed using aniline blue (AB) staining and TUNEL assay. The mean m5C levels were similar between the investigated chromosome structural aberrations carriers (P) and controls (K). However, sperm chromatin integrity tests revealed significantly higher values in chromosomal rearrangement carriers than in controls (P < 0.05). Although the potential relationship between sperm chromatin integrity status and sperm DNA fragmentation and the m5C level juxtaposed in both analyzed groups (P vs K) was represented in a clearly opposite manner, the low chromatin integrity might be associated with the high hypomethylation status of the sperm DNA observed in carriers of chromosome structural aberrations.