SARS-CoV-2 is a novel coronavirus first identified in December 2019. Notable features make SARS-CoV-2 distinct from most other previously-identified Betacoronaviruses, including the receptor binding domain of SARS-CoV-2 and a unique insertion of twelve nucleotide or four amino acids (PRRA) at the S1/S2 boundary. In this study, we identified two deletion variants of SARS-CoV-2 that either directly affect the polybasic cleavage site itself (NSPRRAR) or a flanking sequence (QTQTN). These deletions were verified by multiple sequencing methods. In vitro results showed that the deletion of NSPRRAR likely does not affect virus replication in Vero and Vero-E6 cells, however the deletion of QTQTN may restrict late phase viral replication. The deletion of QTQTN was detected in 3 of 68 clinical samples and half of 24 in vitro isolated viruses, whilst the deletion of NSPRRAR was identified in 3 in vitro isolated viruses. Our data indicate that (i) there may be distinct selection pressures on SARS-CoV-2 replication or infection in vitro and in vivo, (ii) an efficient mechanism for deleting this region from the viral genome may exist, given that the deletion variant is commonly detected after two rounds of cell passage, and (iii) the PRRA insertion, which is unique to SARS-CoV-2, is not fixed during virus replication in vitro. These findings provide information to aid further investigation of SARS-CoV-2 infection mechanisms and a better understanding of the NSPRRAR deletion variant observed here. Important notes The spike protein determines the infectivity and host range of coronaviruses. SARS-CoV-2 has two unique features in its spike protein, the receptor binding domain and an insertion of twelve nucleotides at the S1/S2 boundary resulting a furin-like cleavage site. Here, we identified two deletion variants of SARS-CoV-2 that either directly affect the furin-like cleavage site itself (NSPRRAR) or a flanking sequence (QTQTN) and investigated these deletions in cell isolates and clinical samples. The absence of the polybasic cleavage site in SARS-CoV-2 did not affect virus replication in Vero or Vero-E6 cells. Our data indicate the PRRAR and its flanking sites are not fixed in vitro, thus there appears to be distinct selection pressures on SARS-CoV-2 sequences in vitro and in vivo. Further investigation of the mechanism of generating these deletion variants and their infectivity in different animal models would improve our understanding of the origin and evolution of this virus.

Our study demonstrated that APRI could diagnose significant liver fibrosis, especially cirrhosis in BA infants, and the elevated preoperative APRI predicts jaundice persistence after KP.

Empty follicle syndrome (EFS) is a condition in which no oocyte is retrieved from mature follicles after proper ovarian stimulation in an in vitro fertilization procedure. Genetic evidence accumulates for the etiology of recurrent EFS without pharmacological or iatrogenic problems. In this study, we present two infertile sisters in a family with EFS after three cycles of standard ovarian stimulation with human chorionic gonadotrophin and/or gonadotropin‐releasing hormone agonist therapy. Via whole‐exome sequencing and cosegregation test, we identified compound heterozygous mutations in the gene of ZP1 in both of the infertile sisters. Coimmunoprecipitation tests and homology modeling analysis confirmed that both mutated ZP1 disrupt the formation of oocyte zona pellucida by interrupting the interaction among ZP1, ZP2, and ZP3. We thus propose that the specific mutations in ZP1 gene render a causality for the intractable EFS.

Cerebral palsy is the most prevalent physical disability in children; however, its inherent molecular mechanisms remain unclear. In the present study, we performed in-depth clinical and molecular analysis on 120 idiopathic cerebral palsy families, and identified underlying detrimental genetic variants in 45% of these patients. In addition to germline variants, we found disease-related postzygotic mutations in approximately 6.7% of cerebral palsy patients. We found that patients with more severe motor impairments or a comorbidity of intellectual disability had a significantly higher chance of harboring disease-related variants. By a compilation of 114 known cerebral-palsy-related genes, we identified characteristic features in terms of inheritance and function, from which we proposed a dichotomous classification system according to the expression patterns of these genes and associated cognitive impairments. In two patients with both cerebral palsy and intellectual disability, we revealed that the defective TYW1, a tRNA hypermodification enzyme, caused primary microcephaly and problems in motion and cognition by hindering neuronal proliferation and migration. Furthermore, we developed an algorithm and demonstrated in mouse brains that this malfunctioning hypermodification specifically perturbed the translation of a subset of proteins involved in cell cycling. This finding provided a novel and interesting mechanism for congenital microcephaly. In another cerebral palsy patient with normal intelligence, we identified a mitochondrial enzyme GPAM, the hypomorphic form of which led to hypomyelination of the corticospinal tract in both human and mouse models. In addition, we confirmed that the aberrant Gpam in mice perturbed the lipid metabolism in astrocytes, resulting in suppressed astrocytic proliferation and a shortage of lipid contents supplied for oligodendrocytic myelination. Taken together, our findings elucidate novel aspects of the etiology of cerebral palsy and provide insights for future therapeutic strategies.

Our findings indicate that patients with BA exhibit a distinct profile of circulating miRNAs and that plasma miR-140-3p may be a promising diagnostic biomarker for this disease.