Mutations in the stromal antigen 3 (STAG3) gene cause male infertility due to meiotic arrest.

STUDY QUESTION: Are sequence variants in the stromal antigen 3 (STAG3) gene a cause for non-obstructive azoospermia (NOA) in infertile human males? SUMMARY ANSWER: Sequence variants affecting protein function of STAG3 cause male infertility due to meiotic arrest. WHAT IS KNOWN ALREADY: In both women and men, STAG3 encodes for a meiosis-specific protein that is crucial for the functionality of meiotic cohesin complexes. Sequence variants in STAG3 have been reported to cause meiotic arrest in male and female mice and premature ovarian failure in human females, but not in infertile human males so far. STUDY DESIGN, SIZE, DURATION: The full coding region of STAG3 was sequenced directly in a cohort of 28 men with NOA due to meiotic arrest. In addition, a larger group of 275 infertile men that underwent whole-exome sequencing (WES) was screened for potential STAG3 sequence variants. Furthermore, meiotic spreads, immunohistochemistry, WES and population sampling probability (PSAP) have been conducted in the index case. PARTICIPANTS/MATERIALS, SETTING, METHODS: This study included 28 infertile but otherwise healthy human males who underwent Sanger sequencing of the full coding region of STAG3. Additionally, WES data of 275 infertile human males with different infertility phenotypes have been screened for relevant STAG3 variants. All participants underwent karyotype analysis and azoospermia factor (AZF) screening in advance. In the index patient, segregation analysis, WES data, PSAP, lab parameters, testis histology and nuclear spreads have been added to suplort the findings. MAIN RESULTS AND THE ROLE OF CHANCE: Two compound-heterozygous variants in STAG3 (c.[1262T>G];[1312C>T], p.[(Leu421Arg)];[(Arg438Ter)]) have been found to cause male infertility due to complete bilateral meiotic arrest in an otherwise healthy human male. Compound heterozygosity was confirmed by Sanger sequencing of the parents and the patient's brother. Other variants which may affect spermatogenesis have been ruled out through analysis of the patient's WES data and application of the PSAP pipeline. As expected from Stag3 knockout-mice meiotic spreads, germ cells did not develop further than zygotene and showed drastic chromosome aberrations. No rare variants in STAG3 were found in the 275 infertile males with other phenotypes. Our results indicate that STAG3 variants that negatively affect its protein function are a rare cause of NOA (<1% of cases). LIMITATIONS, REASONS FOR CAUTION: We identified only one patient with compound-heterozygous variants in STAG3 causing NOA due to meiotic arrest. Future studies should evaluate STAG3 variants in larger cohorts to support this finding. WIDER IMPLICATIONS OF THE FINDINGS: Identification of STAG3 sequence variants in infertile human males should improve genetic counselling as well as diagnostics and treatment. Especially before testicular sperm extraction (TESE) for ICSI, STAG3 variants should be ruled out to prevent unnecessary interventions with frustrating outcomes for both patients and clinicians. STUDY FUNDING/COMPETING INTEREST(S): This work was carried out within the frame of the German Research Foundation (DFG) Clinical Research Unit 'Male Germ Cells: from Genes to Function' (CRU326). Work in the laboratory of R.J. is supported by a grant of the European Union H2020 program GermAge. The authors declare no conflicts of interest. TRIAL REGISTRATION NUMBER: Not applicable.

Coronary or thoracic artery calcium score in provoked and unprovoked pulmonary embolism: a case-control study.

UNLABELLED: Essentials Patients with unprovoked pulmonary embolism (PE) are at increased risk of arterial thromboembolism. Coronary and thoracic aorta calcium were evaluated in patients with and without (unprovoked) PE. No association was found between (unprovoked) PE and coronary or aortic calcification. Assessment of both calcium scores on computed tomography pulmonary angiography was highly reproducible. SUMMARY: Objective To evaluate the potential association between (unprovoked) pulmonary embolism (PE) and the presence and extent of coronary artery calcium (CAC) and thoracic aorta calcium (TAC). Methods CAC and TAC derived from computed tomography pulmonary angiography of 100 patients with PE were compared to that of 100 patients in whom PE was ruled out. Results Intraobserver and interobserver agreements for both TAC and CAC were excellent (intraclass correlation > 0.95 for both). In patients with PE vs. patients without PE, no significant differences were found in the presence of CAC or TAC (CAC 64% vs. 67%, odds ratio [OR] 1.0, 95% confidence interval [CI] 0.67-1.6; TAC 46% vs. 59%, OR 1.2, 95% CI 0.80-2.1). Mean CAC and TAC scores were significantly lower in patients with PE than in patients without PE (CAC 3.4 vs. 4.9, absolute difference 1.5, 95% CI 0.2-2.8; TAC 1.1 vs. 1.8, absolute difference 0.9, 95% CI 0.2-1.2). No significant differences were found in the presence of CAC or TAC or in mean CAC and TAC scores between patients with unprovoked PE vs. patients with provoked PE, or between patients with unprovoked PE vs. no PE. Conclusion No significant differences were found between the extent of CAC and TAC in patients with unprovoked PE compared to those with provoked PE or without PE. The observed difference in the extend of CAC and TAC between patients with and without PE was dependent on prevalent cardiovascular risk factors.

Right ventricular function and thrombus load in patients with pulmonary embolism and diagnostic delay.

INTRODUCTION: It has been reported that the time between symptom onset and objective diagnosis of pulmonary embolism (PE) does not affect patients' prognosis with regard to re-thrombosis and mortality risk. However, this observation is contra-intuitive and poorly understood. We further elaborated on this paradox by evaluating thrombus load and right ventricular function in patients with and without diagnostic delay. MATERIALS AND METHODS: We performed a post hoc analysis of a previously published observational prospective outcome study in 113 consecutive PE patients. Qanadli-score and RV/LV ratio were scored in all patients, as was the duration from symptom onset to clinical presentation and diagnosis. Diagnostic delay was defined as a period of more than 7 days between symptom onset and clinical presentation. Further endpoints were mortality and hospital readmission in a 6-week follow-up period. RESULTS: Twenty patients with and 93 patients without delay were studied, who had comparable baseline characteristics and co-morbidities. In linear analyses, Qanadli-score (R² of 0.021; P = 0.130) and RV/LV ratio (R² < 0.001; P = 0.991) were not associated with diagnostic delay. Likewise, longer delay was not predictive of 6-week mortality (odds ratio, 0.65; 95% CI, 0.08-5.57) or hospital readmission (odds ratio, 0.75; 95% CI, 0.15-3.65). CONCLUSION: In our patient cohort, diagnostic delay was not associated with higher thrombus load or right ventricular dysfunction. This provides a possible explanation for the lack of prognostic relevance of diagnostic delay.