A novel missense variant expands the phenotype and genotype of PAX6-associated foveal hypoplasia accompanied by various manifestations of anterior segment dysgenesis.

BACKGROUND: According to previous reports, PAX6-associated foveal hypoplasia (FH) could usually be accompanied by various anterior segment anomalies including variable iris changes. This study aims to exhibit unusual phenotypes of a novel missense variant of PAX6 from a Chinese pedigree. METHODS: Ophthalmic examinations including slit-lamp biomicroscopy, gonioscopy, ophthalmic ultrasound, ultrasonic biomicroscopy, optical coherence tomography, wide-field fundus imaging, and visual field test were performed to evaluate the clinical manifestations. Whole-exome sequencing (WES) and bioinformatics analysis were conducted in eight members from this pedigree to identify the causative mutation. RESULTS: WES revealed a novel heterozygous substitution of PAX6 (NM_000280.5:c.157G > A, p.(Val53Met) (chr11:31823309 C > T, hg19)), which cosegregated with the phenotype of this pedigree. All the three patients (a pair of fraternal twins and their mother) exhibited bilateral FH and anterior segment dysgenesis (ASD) including microcornea, sclerocornea, obvious symmetrical corectopia, iris stromal dysplasia, goniodysgenesis, and abnormal distribution of fundus blood vessels. The girl of the fraternal twins also demonstrated bilateral temporal deviation of lenses and abnormal tissue membrane connecting anterior chamber angle and lens anterior capsule in the right eye. The mother additionally showed apparent cataract bilaterally and cupping of the optic disc in her left eye. CONCLUSION: A novel missense variant in PAX6 gene was detected in a Chinese pedigree demonstrating bilateral FH and ASD. It is really distinctive that the ASD involves almost all parts of the anterior segment, and bilateral symmetrical corectopia is the most perceptible sign. This study expands the phenotypic and genotypic spectrum of PAX6-associated ocular diseases, and facilitates the understanding of the crucial role that PAX6 plays in the development of the eye. Meanwhile, PAX6 could be considered as a candidate pathogenic gene of bilateral symmetrical corectopia.

Efficacy of dehydroepiandrosterone priming in women with poor ovarian response undergoing IVF/ICSI: a meta-analysis.

Background: Dehydroepiandrosterone (DHEA) may improve the outcomes of patients with poor ovarian response (POR) or diminished ovarian reserve (DOR) undergoing IVF/ICSI. However, the evidence remains inconsistent. This study aimed to investigate the efficacy of DHEA supplementation in patients with POR/DOR undergoing IVF/ICSI. Methods: PubMed, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI) were searched up to October 2022. Results: A total of 32 studies were retrieved, including 14 RCTs, 11 self-controlled studies and 7 case-controlled studies. In the subgroup analysis of only RCTs, DHEA treatment significantly increased the number of antral follicle count (AFC) (weighted mean difference : WMD 1.18, 95% confidence interval(CI): 0.17 to 2.19, P=0.022), while reduced the level of bFSH (WMD -1.99, 95% CI: -2.52 to -1.46, P<0.001), the need of gonadotropin (Gn) doses (WMD -382.29, 95% CI: -644.82 to -119.76, P=0.004), the days of stimulation (WMD -0.90, 95% CI: -1.34 to -0.47, P <0.001) and miscarriage rate (relative risk : RR 0.46, 95% CI: 0.29 to 0.73, P=0.001). The higher clinical pregnancy and live birth rates were found in the analysis of non-RCTs. However, there were no significant differences in the number of retrieved oocytes, the number of transferred embryos, and the clinical pregnancy and live birth rates in the subgroup analysis of only RCTs. Moreover, meta-regression analyses showed that women with lower basal FSH had more increase in serum FSH levels (b=-0.94, 95% CI: -1.62 to -0.25, P=0.014), and women with higher baseline AMH levels had more increase in serum AMH levels (b=-0.60, 95% CI: -1.15 to -0.06, P=0.035) after DHEA supplementation. In addition, the number of retrieved oocytes was higher in the studies on relatively younger women (b=-0.21, 95% CI: -0.39 to -0.03, P=0.023) and small sample sizes (b=-0.003, 95% CI: -0.006 to -0.0003, P=0.032). Conclusions: DHEA treatment didn't significantly improve the live birth rate of women with DOR or POR undergoing IVF/ICSI in the subgroup analysis of only RCTs. The higher clinical pregnancy and live birth rates in those non-RCTs should be interpreted with caution because of potential bias. Further studies using more explicit criteria to subjects are needed. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD 42022384393.

Toxin-Antitoxin Systems Alter Adaptation of Mycobacterium smegmatis to Environmental Stress.

Toxin-antitoxin (TA) systems are ubiquitous genetic elements in prokaryotes, but their biological importance is poorly understood. Mycobacterium smegmatis contains eight putative TA systems. Previously, seven TAs have been studied, with five of them being verified as functional. Here, we show that Ms0251-0252 is a novel TA system in that expression of the toxin Ms0251 leads to growth inhibition that can be rescued by the antitoxin Ms0252. To investigate the functional roles of TA systems in M. smegmatis, we deleted the eight putative TA loci and assayed the mutants for resistance to various stresses. Deletion of all eight TA loci resulted in decreased survival under starvation conditions and altered fitness when exposed to environmental stresses. Furthermore, we showed that deletion of the eight TA loci decreased resistance to phage infection in Sauton medium compared with the results using 7H10 medium, suggesting that TA systems might have different contributions depending on the nutrient environment. Furthermore, we found that MazEF specifically played a dominant role in resistance to phage infection. Finally, transcriptome analysis revealed that MazEF overexpression led to differential expression of multiple genes, including those related to iron acquisition. Altogether, we demonstrate that TA systems coordinately function to allow M. smegmatis to adapt to changing environmental conditions. IMPORTANCE Toxin-antitoxin (TA) systems are mechanisms for rapid adaptation of bacteria to environmental changes. Mycobacterium smegmatis, a model bacterium for studying Mycobacterium tuberculosis, encodes eight putative TA systems. Here, we constructed an M. smegmatis mutant with deletions of all eight TA-encoding genes and evaluated the resistance of these mutants to environmental stresses. Our results showed that different TA systems have overlapping and, in some cases, opposing functions in adaptation to various stresses. We suggest that complementary TA modules may function together to regulate the bacterial stress response, enabling adaptation to changing environments. Together, this study provides key insights into the roles of TA systems in resistance to various environmental stresses, drug tolerance, and defense against phage infection.