Whole-Genome Sequencing Reveals Exonic Variation of ASIC5 Gene Results in Recurrent Pregnancy Loss

Whole exome sequencing identifies a novel mutation in Annexin A4 that is associated with recurrent spontaneous abortion

Background

Recurrent spontaneous abortion (RSA) is a multifactorial disease, the exact causes of which are still unknown. Environmental, maternal, and genetic factors have been shown to contribute to this condition. The aim of this study was to investigate the presence of mutations in the ANXA4 gene in patients with RSA.

Methods

Genomic DNA was extracted from 325 patients with RSA and 941 control women with a normal reproductive history for whole-exome sequencing (WES). The detected variants were annotated and filtered, and the pathogenicity of the variants was predicted through the SIFT online tool, functional enrichment analyses, Sanger sequencing validation, prediction of changes in protein structure, and evolutionary conservation analysis. Furthermore, plasmid construction, Western blotting, RT-qPCR, and cell migration, invasion and adhesion assays were used to detect the effects of ANXA4 mutations on protein function.

Results

An ANXA4 mutation (p.G8D) in 1 of the 325 samples from patients with RSA (RSA-219) was identified through WES. This mutation was not detected in 941 controls or included in public databases. Evolutionary conservation analysis revealed that the amino acid residue affected by the mutation (p.G8D) was highly conserved among 13 vertebrate species, and the SIFT program and structural modeling analysis predicted that this mutation was harmful. Furthermore, functional assays revealed that this mutation could inhibit cell migration, invasion and adhesion.

Conclusion

Our study suggests that an unreported novel ANXA4 mutation (p.G8D) plays an important role in the pathogenesis of RSA and may contribute to the genetic diagnosis of RSA.

High Incidence of CPLANE1-Related Joubert Syndrome in the Products of Conceptions from Early Pregnancy Losses

Background

The fetal monogenic causes of early pregnancy losses (EPLs) are mainly unknown, with only a few articles on the subject published. In our previous study of EPLs using whole-exome sequencing analysis, we confirmed a genetic diagnosis of CPLANE1-related Joubert syndrome (JS) in three EPLs from two couples and identified a relatively common CPLANE1 allele among our population (NM_001384732.1:c.1819delT;c.7817T>A, further after referred as “complex allele”). Pathogenic variants in the CPLANE1 (C5orf42) gene are reported to cause JS type 17, a primary ciliopathy with various system defects.

Aims

To examine the hypothesis that the CPLANE1 “complex allele,” whether homozygous or compound heterozygous, is a common cause of EPLs in our population.

Study Design

Cohort study/case-control study.ontrol study.

Methods

In this study, we used polymerase chain reaction-based methods to screen for CPLANE1 “complex allele” presence among 246 euploid EPLs (< 12 gestational weeks) from families in North Macedonia. We also investigated the impact of this allele in 650 women with EPLs versus 646 women with no history of pregnancy loss and at least one livebirth, matched by ethnic origin.

Results

We found a high incidence of JS in the total study group of EPLs (2.03%), with a considerably higher incidence among Albanian families (6.25%). Although not statistically significant, women with EPLs had a higher allele frequency of the CPLANE1 “complex allele” (AF = 1.38%) than the controls (AF = 0.85%; p = 0.2). Albanian women had significantly higher frequency of the “complex allele” than the Macedonians (AF = 1.65% and 0.39%, respectively; p = 0.003).

Conclusion

To the best of our knowledge, this is the highest reported incidence of fetal monogenic disease that might cause EPLs. Targeted screening for the CPLANE1 “complex allele” would be warranted in Albanian ethnic couples because it would detect one JS in every 16 euploid EPLs. Our findings have a larger impact on the pathogenesis of pregnancy loss and contribute to a better understanding of the pathogenicity of the variants in the CPLANE1 gene.

Angiotensin-Converting Enzyme (ACE) Insertion/Deletion (I/D) Polymorphism as a Conjoint Regulator of Coagulation, Fibrinolytic, and RAAS Pathway in Infertility and Associated Pregnancy Complications

Despite the increase in assisted reproductive technologies, the high rates of infertility and pregnancy complications are a major concern to infertility specialists worldwide. Infertility may be attributed to pregnancy complications like thrombophilia, preeclampsia and fibrin-induced recurrent pregnancy loss (RPL). Renin-angiotensin-aldosterone system (RAAS) directly or indirectly causes preeclampsia and thrombophilia through the fibrinolytic pathway that ultimately leads to RPL or infertility. The underlying mechanisms of this interaction are still unclear. The present comprehensive review is intended to demonstrate the role and interaction of RAAS and fibrinolytic pathways in pregnancy complications. How this interaction can induce pregnancy complications, and ultimately infertility, is also discussed in the light of current evidence. This study also presents common markers that link RAAS and fibrinolytic processes in developing thrombophilia, preeclampsia and RPL. The common link in these pathways is ACE gene I/D polymorphism. Apart from ACE, PAI-1, VIIa, XIIa, AT1R, AT1AA, and TF are common molecules that can delineate the underlying causes of pregnancy complications and infertility.

Effects of oocyte vitrification on gene expression in the liver and kidney tissues of adult offspring

Oocyte vitrification is an important assisted reproductive technology (ART) that preserves the fertility of unmarried patients with malignant tumors, and promotes the development of the oocyte donation program. In recent years, the effects of ART, including the vitrification of oocytes and embryos on the health of offspring, have attracted much attention; however, it is difficult to conduct long-term follow-up and biochemical evaluation in humans. In this study, we detected the effect of oocyte vitrification on gene expression in the organs of adult mice offspring by RNA sequencing for the first time. Our results showed that only a small amount of gene expression was significantly affected. Seven genes (Tpm3, Hspe1-rs1, Ntrk2, Cyp4a31, Asic5, Cyp4a14, Retsat) were abnormally expressed in the liver, and ten genes (Lbp, Hspe1-rs1, Prxl2b, Pfn3, Gm9008, Bglap3, Col8a1, Hmgcr, Ero1lb, Ifi44l) were abnormal in the kidney. Several genes were related to metabolism and disease occurrence in the liver or kidney. Besides, we paid special attention to the expression of known imprinted genes and DNA methylation-related genes in adult organs, which are susceptible to oocyte cryopreservation in the preimplantation stage. As a result, some of these transcripts were detected in adult organs, but they were not affected by oocyte vitrification. In conclusion, we first report that oocyte vitrification did not significantly change the global gene expression in offspring organs; nonetheless, it can still influence the transcription of a few functional genes. The potential adverse effects caused by oocyte vitrification need attention and further study.

Heterogeneity in biomarkers, mitogenome and genetic disorders of the Arab population with special emphasis on large-scale whole-exome sequencing

More than 25 million DNA variations have been discovered as novel including major alleles from the Arab population. Exome studies on the Saudi genome discovered > 3000 novel nucleotide variants associated with > 1200 rare genetic disorders. Reclassification of many pathogenic variants in the Human Gene Mutation Database and ClinVar Database as benign through the Arab database facilitates building a detailed and comprehensive map of the human morbid genome. Intellectual disability comes first with the combined and observed carrier frequency of 0.06779 among Saudi Arabians; retinal dystrophy is the next highest. Genome studies have discovered interesting novel candidate disease marker variations in many genes from consanguineous families. More than 7 pathogenic variants in the C12orf57 gene are prominently associated with the etiology of developmental delay/intellectual impairment in Arab ancestries. Advances in large-scale genome studies open a new outlook on Mendelian genes and disorders. In the past half-dozen years, candidate genes of intellectual disability, neurogenetic disorders, blood and bleeding disorders and rare genetic diseases have been well documented through genomic medicine studies in combination with advanced computational biology applications. The Arab mitogenome exposed hundreds of variations in the mtDNA genome and ancestral sharing with Africa, the Near East and East Asia and its association with obesity. These recent discoveries in disease markers and molecular genetics of the Arab population will have a positive impact towards supporting genetic counsellors on reaching consanguineous families to manage stress linked to genetics and precision medicine. This narrative review summarizes the advances in molecular medical genetics and recent discoveries on pathogenic variants. Despite the fact that these initiatives are targeting the genetics and genomics of disorders prevalent in Arab populations, a lack of complete cooperation across the projects needed to be revisited to uncover the Arab population's prominent disease markers. This shows that further study is needed in genomics to fully comprehend the molecular abnormalities and associated pathogenesis that cause inherited disorders in Arab ancestries.

Fetal Nucleated Red Blood Cells Preferable Than Cell-Free Fetal DNA for Early Determination of Gender Among Invasive and Non-Invasive Source Using Novel Four Genes Multiplex PCR

Background

Deoxyribonucleic acid from invasive, non-invasive and 9th week embryo can be a resource for the determination of fetal sex using highly sensitive and specific multiplex PCR.

Methods

A total of 402 DNA samples were used to test the newly developed novel multiplex PCR including male specific (3 genes: SRY, DAZ2 and TSPY1) Y-biomarkers and internal control, ACTB. The study isolated cffDNA (Cell-free fetal DNA; n = 73) from mother’s plasma, serum and urine, fetal DNA from 9th week embryo and cord blood, and fetal DNA from CD71^+ve nucleated red blood cells (fNRBC; n = 73). Paternal and maternal DNA from buccal cells (n = 20) and blood (n = 232) used for male and female confirmation.

Results

The study observed that SRY alone cannot be a suitable Y-biomarker. Confirmation from any two Y-biomarkers is mandatory for male fetus identification. Direct sequencing of the gel eluted multiplex and single amplicons confirmed the specific sequences. Presence of two out of 3 Y-biomarkers OR single Y-biomarker with >1,000,000 intensity is considered positive for male. The multiplex PCR is suitable for determining sex from all source of fetal DNA including highly degraded cffDNA and can detect the sex using 0.5ng DNA. Individual marker-based real-time qPCR followed by combined melt curve analysis showed distinguished melt curve peaks for the markers.

Conclusion

The multiplex PCR achieved 100% accuracy on fetal DNA from fNRBC for early determinations (<13 weeks) of gender. The developed novel and simple multiplex PCR and individual qPCR can be adopted in all types of laboratories for determining human fetal gender using fetal DNA from fNRBC. Early identification of gender can support to prepare for possible X-linked analysis, reduce anxiety in mother, strengthen a bond between mother and fetus, and effective decision making. Non-invasive source of fetal DNA from fNRBC preferred for identifying gender to reduce the risk of invasive procedures in early (8–13 weeks) pregnancy.

Congenital nephrotic syndrome in a Hispanic Guatemalan newborn associated with a NPHS1 variant: A case report

Congenital nephrotic syndrome (CNS) is an autosomal recessive disorder usually detected in the first 3 months of life when the syndromes effects manifest, including edema and a failure to gain weight. A baby boy was admitted to the Neonatal Intensive Care Unit for prematurity (35 weeks) with unremarkable maternal prenatal laboratory tests. The patient had persistent systemic hypertension, hypoproteinemia, hypoalbuminemia and nephrotic range proteinuria. CNS was diagnosed, and genetic testing showed a homozygous variant, c.3024A>G (AGA>AGG) in exon 22 of the nephrin locus. Bioinformatics analysis suggested the genetic condition was likely a result of malfunctional DNA binding sites of transcription factors FOXL1 and FOXC1.