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Background
Alport syndrome, a monogenic kidney disease, is characterized by progressive hemorrhagic nephritis, sensorineural hearing loss, and ocular abnormalities. Mutations in COL4A5 at Xq22 accounts for 80–85% of X-linked Alport syndrome patients. Three couples were referred to our reproductive genetics clinic for prenatal or preconception couns...
Contexts in source publication
Context 1
... DNA of the four families, including probands in each pedigree, were extracted from peripheral blood samples according to standard procedures. Target regions of the COL4A5 were amplified with specific primers (Supplementary Table 1) and were subsequently sequenced on an Applied Biosystems 3500Dx sequencer. The primers were designed with the Primer 3 Web ( Untergasser et al., 2012). ...Context 2
... couples were referred to the reproductive genetics clinic of the International Peace Maternity and Child Health Hospital (IPMCH) for preconception or prenatal counseling. Two naturally pregnant patients (Table 1, Nos. 1 and 2), 37 and 41 years old respectively, had given birth to children affected with Alport syndrome, and one 32-year-old patient ( Table 1, Nos. 3) had a history of ectopic pregnancy and family history of Alport syndrome. Pathogenic COL4A5 mutations (c.1834G > C; c.888_889del; c.1933C > T) were validated in the three women by Sanger sequencing (Figure 1). ...Citations
... Therefore, we used MALBAC for gene amplification of trophoblast cells. While other reports describe the application of PGT-M in XLAS (28,29), this is the first use of the MALBAC technique for WGA. In order to reduce the impact of ADO, we used polymorphic markers from the proband and his parents and linkage analysis of mutant genes to establish haplotypes. ...
X-Linked Alport Syndrome (XLAS) is an X-linked, dominant, hereditary nephropathy mainly caused by mutations in the COL4A5 gene, found on chromosome Xq22. In this study, we reported a pedigree with XLAS caused by a COL4A5 mutation. This family gave birth to a boy with XLAS who developed hematuria and proteinuria at the age of 1 year. We used next-generation sequencing (NGS) to identify mutations in the proband and his parents and confirmed the results using Sanger sequencing. This testing showed there was a single nucleotide missense variation, c.3659G>A (p.Gly1220Asp) (NM_033380.3), in the COL4A5 gene. To prevent the inheritance of the syndrome, we used eight embryos for trophoblast biopsy after assisted reproductive technology treatment, and whole genome amplification (WGA) was performed using multiple annealing and looping-based amplification cycles (MALBAC). Embryos were subjected to Preimplantation Genetic Testing (PGT) procedures, including Sanger sequencing, NGS-based single nucleotide polymorphism (SNP) haplotype linkage analysis, and chromosomal copy number variation (CNV) analysis. The results showed that three embryos (E1, E2, and E4) were free of CNV and genetic variation in the COL4A5 gene. Embryo E1 (4AA) was transferred after consideration of the embryo growth rate, morphology, and PGT results. Prenatal diagnosis in the second trimester showed that the fetus had a normal karyotype and did not carry the COL4A5 mutation (c.3659G>A). Ultimately, a healthy boy was born and did not carry the pathogenic COL4A5 mutation, which indicated that PGT prevented the intergenerational transmission of the causative mutation of XLAS.
... However, attitudes towards PND and PGT for non-lethal disorders such as HL vary greatly depending upon the culture, financial status, and religion of the at-risk individuals, as well as government policies. These factors, combined with the complex technical processes, have resulted in fewer PGT cases with HL being reported (Table S1) [9][10][11][12][13][14][15][16][17] than are in cases of another monogenic disease such as Huntington disease, cystic fibrosis, and neurofibromatosis. ...
Purpose
To evaluate the clinical validity of preimplantation genetic testing (PGT) to prevent hereditary hearing loss (HL) in Chinese population.
Methods
A PGT procedure combining multiple annealing and looping-based amplification cycles (MALBAC) and single-nucleotide polymorphisms (SNPs) linkage analyses with a single low-depth next-generation sequencing run was implemented. Forty-three couples carried pathogenic variants in autosomal recessive non-syndromic HL genes, GJB2 and SLC26A4, and four couples carried pathogenic variants in rare HL genes: KCNQ4, PTPN11, PAX3, and USH2A were enrolled.
Results
Fifty-four in vitro fertilization (IVF) cycles were implemented, 340 blastocysts were cultured, and 303 (89.1%) of these received a definite diagnosis of a disease-causing variant testing, linkage analysis and chromosome screening. A clinical pregnancy of 38 implanted was achieved, and 34 babies were born with normal hearing. The live birth rate was 61.1%.
Conclusions and relevance
In both the HL population and in hearing individuals at risk of giving birth to offspring with HL in China, there is a practical need for PGT. The whole genome amplification combined with NGS can simplify the PGT process, and the efficiency of PGT process can be improved by establishing a universal SNP bank of common disease-causing gene in particular regions and nationalities. This PGT procedure was demonstrated to be effective and lead to satisfactory clinical outcomes.
... PGT refers to the genetic analysis of an embryo, involving multiple assisted reproductive procedures, including superovulation, intracytoplasmic sperm injection (ICSI), in vitro embryo culture, blastomere biopsy, vitrification, and genetic testing. It has been sophisticatedly used for preventing abnormal pregnancy in hereditary monogenic disorders, aneuploidy, and chromosomal rearrangements (Handyside et al., 1990;Shi et al., 2021). Recently, a cohort study assessed and demonstrated the transmission of gonadal mosaic mutations to preimplantation blastocysts with PGT (Breuss et al., 2022). ...
... For PND, amniocentesis was performed at the 16th gestational week. Amniotic fluid cells were used for chromosomal karyotyping, genomic CNV sequencing, and Sanger sequencing for the verification of chromosomal normality and the absence of pathogenic SMARCA2 variants as previously described (Shi et al., 2021). ...
Objective: Paternal sperm mosaicism has few consequences for fathers for mutations being restricted to sperm. However, it could potentially underlie severe sporadic disease in their offspring. Here, we present a live birth of a female infant from a father with low-level sperm DNA mosaicism achieved via preimplantation genetic testing for monogenic disorders (PGT-M).
Methods: A couple with the father carrying sperm DNA mosaicism received standard in vitro fertilization treatment, with intracytoplasmic sperm injection, embryo biopsy, polymerase chain reaction, and DNA analysis. Only one unaffected embryo was transferred to the uterine cavity. Amniocentesis was performed at the 16th week of gestation by copy-number variation-sequencing, karyotyping, and Sanger sequencing.
Results: Eight surviving embryos were biopsied during the blastocyst stage. Karyomapping and Sanger sequencing were applied to detect the euploidy and paternal mutation. After performing PGT-M, followed by successful pregnancy, the prenatal genetic diagnoses revealed that the fetus was unaffected, and one healthy girl was born.
Conclusion: This is the first reported live birth with unaffected children achieved via PGT for a low-level germline mosaicism father. It not only opens the possibility of preventing the recurrent monogenic disease of children among gonadal mosaicism families but also alerts clinicians to consider gonadal mosaicism as the source of DMNs.
... Next-generation sequencing and similar technologies allow researchers to investigate the significance of disease-associated variants cost-effectively and quickly for clinical diagnoses [20][21][22][23][24][25]. Consistency between the significance of disease-associated variants is necessary [16,17]. ...
... There was a delay in the diagnosis and monitoring of this patient because she did not have routine follow up and care with a nephrologist. Second, she had multiple pregnancies, which in turn can accelerate CKD progression [23]. Aside from her disease course, patient 1 exhibited the most common symptoms associated with AS, hematuria and proteinuria. ...
Background
Alport syndrome is a hereditary kidney disease characterized by hematuria and proteinuria. Although there have been reports of autosomal dominant COL4A4 variants, this is likely an underdiagnosed condition. Improved access to affordable genetic testing has increased the diagnosis of Alport syndrome. As genetic testing becomes ubiquitous, it is imperative that clinical nephrologists understand the benefits and challenges associated with clinical genetic testing.
Case Presentation
We present a family of Mexican descent with a heterozygous COL4A4 variant (c.5007delC, ClinVar accession numbers: SCV001580980.2, SCV001993731.1) not previously discussed in detail in the literature. The proband received a biopsy diagnosis suggestive of Fabry disease 18 years after she first developed hematuria and progressed to chronic kidney disease stage III. One year later, the proband was provisionally diagnosed with Alport syndrome after a variant of uncertain significance in the COL4A4 gene was identified following targeted family variant testing of her daughter. Upon review of the medical histories of the proband’s children and niece, all but one had the same variant. Of the four with the variant, three display clinical symptoms of hematuria, and/or proteinuria. The youngest of the four, only months old, has yet to exhibit clinical symptoms. Despite these findings there was a considerable delay in synthesizing this data, as patients were tested in different commercial genetic testing laboratories. Subsequently, understanding this family’s inheritance pattern, family history, and clinical symptoms, as well as the location of the COL4A4 variant resulted in the upgrade of the variant’s classification. Although the classification of this variant varied among different clinical genetic testing laboratories, the consensus was that this variant is likely pathogenic.
Conclusions
This COL4A4 variant (c.5007delC) not yet discussed in detail in the literature is associated with Alport syndrome. The inheritance pattern is suggestive of autosomal dominant inheritance. This report highlights the intricacies of variant interpretation and classification, the siloed nature of commercial genetic testing laboratories, and the importance of a thorough family history for proper variant interpretation. Additionally, the cases demonstrate the varied clinical presentations of Alport syndrome and suggest the utility of early screening, diagnosis, monitoring, and treatment.
... This approach thereby greatly reduces the chance of having a pregnancy affected with the genetic disease. Since the initial practice of PGT in the monogenetic disorders in 1990s (5), it has been extensively employed in the diagnosis of monogenic disease, X-linked disorders, aneuploidy, and chromosomal rearrangements (3,(6)(7)(8)(9)(10). Carrier screening is becoming standard practice for egg and sperm donors and couples seeking assisted reproduction, due to the introduction of target panels that screen for multiple variants in low risk Abbreviations: AD, autosomal dominant; AR, autosomal recessive; ART, assisted reproductive technology; ACMG, the American College of Medical Genetics and Genomics; BPR, biochemical pregnancy rate; CAKUT, congenital anomalies of the kidney and the urinary tract; CKD, chronic kidney disease; CNV, copy number variations; COH, controlled ovarian hyperstimulation; CSA, clinical sequence analyser; E2, estradiol; ECS, expanded carrier screening; ESRD, endstage renal disease; FHB, fetal heartbeat; FETs, frozenembryo transfers; GnRH, gonadotrophic releasing hormone; HGVS, human genome variation society; hCG, human chorionic gonadotropin; ICSI, intracytoplasmic sperm injection; IR, implantation rate; IVF, in vitro fertilization; MII, metaphase II stage; NGS, next-generation sequencing; NS, nephrotic syndrome; NPHP, nephronophthisis; OP/LBR, ongoing pregnancy/live birth rate; PGT, preimplantation genetic testing; PGT-A, PGT for aneuploidies; PGT-SR, PGT for structural rearrangements; PGT-M, preimplantation genetic testing for monogenic disease; PHCG, positive-human chorionic gonadotropin; PKD, polycystic kidney disease; PND, invasive prenatal diagnosis; TE, trophectoderm; SAB, spontaneous abortion; SNP, single nucleotide polymorphism; WES, whole exome sequencing; WGS, whole genome sequencing. ...
... birth defect (27,42.2%) with some overlaps of abnormal pregnancy (8). Only 17 (26.6%) ...
Background
Genetic kidney disease is a major cause of morbidity and mortality in neonates and end-stage renal disease (ESRD) in children and adolescents. Genetic diagnosis provides key information for early identification of congenital kidney disease and reproductive risk counseling. Preimplantation genetic testing for monogenic disease (PGT-M) as a reproductive technology helps prospective parents to prevent passing on disease-causing mutations to their offspring.Materials and MethodsA retrospective cohort of couples counseled on PGT who had a risk to given birth to a child with genetic kidney disease or had a history of prenatal fetal kidney and urinary system development abnormalities from 2011 to 2021. Through a combination of simultaneously screening for aneuploidy and monogenic kidney disease, we achieved reproductive genetic intervention.ResultsA total of 64 couples counseled on PGT for monogenic kidney disease in a single reproductive center during the past 10 years, of whom 38 different genetic kidney diseases were identified. The most frequent indications for referral were autosomal recessive disease (54.7%), then autosomal dominant disease (29.7%), and X-linked disease (15.6%). Polycystic kidney disease was the most common diseases counted for 34.4%. After oocyte-retrieval in all of 64 females, a total of 339 embryos were diagnosed and 63 embryos were transferred in succession. Among 61 cycles of frozen-embryo transfer (FET), ongoing pregnancy/live birth rate (OP/LBR) reached 57.38%. The cumulative OP/LBR in our cohort for the 64 couples was 54.69%. In addition, we have carried out expanded carrier screening (ECS) in all the in vitro fertilization (IVF) couples performed PGT covering 7,311 individuals. The carrier frequency of the candidate genes for monogenic kidney diseases accounted for 12.19%.Conclusion
Overall, the customization PGT-M plan in our IVF center is pivotal to decreasing the morbidity and implementing reproductive genetic intervention of genetic kidney disease.
... In our case, the affected mother (II-3) did not have clinically detectable abnormalities, except for microscopic hematuria, even after she had given birth to 2 full-term babies. To date, 33 pregnancies have been reported in 23 women with different types of AS [24][25][26][27][28][29]. Among the affected women, 22 received a genetic diagnosis of AS, which included 16 women with XLAS, 4 with ARAS, and 2 patients with ADAS. ...
... In our study, prenatal diagnosis of a DNA sample from the amniotic fluid of the pregnancy was consistent with the PGT-M results, and a healthy baby boy was born at 38 gestational weeks. While NGS has been used in clinical practice for PGT-M, to the best of our knowledge, its detailed use for AS has only been described recently [24]. ...
Background:
Alport syndrome (AS) is a hereditary renal basement membrane disease that can lead to end-stage renal disease in young adults. It can be diagnosed by genetic analysis, being mostly caused by mutations in COL4A3, COL-4A4, and COL4A5. To date, there is no radical cure for this disease.
Objectives:
The aim of this study was to avoid the transmission of AS within an affected family by selecting healthy embryos for uterine transfer. The embryos were identified by preimplantation genetic testing for monogenic disorders (PGT-M).
Methods:
We used next-generation sequencing (NGS) to identify mutations in the proband and his parents. The results of NGS were confirmed by Sanger sequencing. Targeted NGS combined with targeted single-nucleotide polymorphism haplotyping was used for the in vitro identification of COL4A5 mutations in human embryos to prevent their intergenerational transmission.
Results:
The c.349_359delGGACCTCAAGG and c.360_361insTGC mutations in COL4A5 were identified in a family affected by X-linked AS. Whole-genome sequencing by NGS with targeted haplotyping was performed on biopsied trophectoderm cells. A healthy baby was born after transfer of a single freeze-thawed blastocyst.
Conclusions:
The use of targeted NGS for identifying diagnostic markers combined with targeted haplotyping is an easy and efficient PGT-M method for preventing intergenerational transmission of AS.
