SARS-CoV-2 as a new global threat has affected global population for one year. Despite the great effort to eradicate this infection, there are still some challenges including different viral presentation, temporal immunity in infected individuals and variable data of viral shedding. We studied 255 COVID-19 suspected individuals to assess the viral shedding duration and also the antibody development against SARS-CoV-2 among the cases. Real Time RT-PCR assay was applied to determine the virus presence and SARS-CoV-2 antibodies were evaluated using SARS-CoV-2 IgM and IgG kits. 113 patients were confirmed for COVID-19 infection. The patients were followed until negative PCR achieved. The median viral shedding among studied population was obtained 34.16 (±17.65) days which was not significantly associated with age, sex and underlying diseases. Shiver and body pain were found in prolonged form of the infection and also patients who had gastrointestinal problems experienced longer viral shedding. Moreover, IgG was present in 84% of patients after 150 days. According to this data, the median viral shedding prolongation was 34.16 days which indicates that 14 days isolation might not be enough for population. In addition, IgG profiling indicated that it is persistent in a majority of patients for nearly 6 months which has brought some hopes in vaccine efficacy and application.

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Prenatal diagnosis of hereditary diseases has substantially altered the way medical geneticists are helping families affected by genetic disorders. However, the risk of miscarriage and fear of invasive diagnostic procedures may discourage many couples from seeking prenatal diagnosis. With the discovery of maternal plasma cell-free fetal DNA, prenatal diagnosis has entered a new era of progress. Cell-free DNA is released during normal physiological functions as well as through the cell death programs of apoptosis and necrosis. It can be found in the plasma and other body fluids. Although this method has the advantage of being noninvasive, it is still rather expensive and requires advanced hardware and comprehensive data analysis. Promising implications of noninvasive prenatal diagnosis methods for the diagnosis of common trisomy disorders have paved the way for the development of more complicated assays of single-gene disorders. Relative mutation dosage and relative haplotype dosage are the most widely implemented assays for noninvasive prenatal diagnosis of single-gene disorders. However, each assay has its own advantages and disadvantages. Relative mutation dosage is based on the droplet digital polymerase chain reaction (PCR) technique which includes quantification features of real-time PCR assays. Relative haplotype dosage is based on next-generation sequencing that includes analysis of the maternal and paternal genome followed by sequencing of maternal plasma cell-free DNA. Co-amplification at a lower denaturation temperature PCR is another approach that is based on forming heteroduplexes between alleles to selectively amplify paternal mutations. In this review, we have described the most common noninvasive prenatal diagnosis approaches and compared their applications in genetic disorder diagnosis with different inheritance patterns. Key words: Cell-free nucleic acids, Prenatal diagnosis, Noninvasive prenatal testing, Single-gene diseases, Non-invasive techniques.

Background: K-Ras mutations rarely occur in breast cancer. However, studies have supported that K-Ras upregulation is involved in breast cancer pathogenesis. Two main K-Ras transcript variants, K-Ras4A and K-Ras4B, arise originate from the alternative splicing of exon 4. In this study, we aimed to evaluate variations in the expression of K-Ras4A and K-Ras4B and their role in breast ductal carcinoma. Methods: Total RNA was extracted from breast tumors, and the NATs were obtained via mastectomy. Patients were selected from new cases of breast cancer with no prior history of chemotherapy. Relative mRNA expression was calculated based on a pairwise comparison between the tumors and the NATs following normalization to the internal control gene. Predictive values of the transcript variants were examined by ROC curve analysis. Results: A statistically significant increase was found in K-Ras4A and K-Ras4B expression with the mean fold changes of 7.58 ( p = 0.01) and 2.47 ( p = 0.001), respectively. The K-Ras4A/K-Ras4B ratio was lower in the tumors than that of the normal tissues. ROC curve analysis revealed the potential of K-Ras4A (AUC: 0.769) and K-Ras4B (AUC: 0.688) in breast cancer prediction. There was also a significant association between K-Ras4B expression and HER2 statues ( p = 0.04). Furthermore, a significant link was detected between K-Ras4A expression and pathological prognostic stages ( p = 0.04). Conclusion: Our findings reveal that the expression levels of K-Ras4A and K-Ras4B is higher in the tumor compared to the normal breast tissues. Increase in K-Ras4A expression was more significant than that of K-Ras4B.