Mother-Son Kidney Transplantation in Patients With X-Linked Alport Syndrome.
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ABSTRACT:
SUBMITTER: Katayama K
PROVIDER: S-EPMC8116725 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Introduction:Alport syndrome (AS) is caused by mutations in ?3/?4/?5 (IV) collagen genes, the severity of which determine the progression of AS. Posttransplantation outcome is good, although anti-glomerular basement membrane (anti-GBM) glomerulonephritis occurs in 3% to 5% of recipients, clustering in patients with a severe mutation. We assessed whether the severity of the underlying AS mutation affects graft and patients outcome after transplantation, including the occurrence of anti-GBM nephritis. Methods:We included 73 AS patients with an identified mutation (COL4A5, 57 patients; COL4A3, 9 patients; COL4A4, 6 patients; heterozygous composite COL4A3 and A4, 1 patient) who underwent transplantation between 1971 and 2014 and who had received a total of 93 kidney grafts. Results:In all, 41 patients had a severe mutation (COL4A5, 30 patients; COL4A3, 6 patients; COL4A4, 5 patients), and 32 had a nonsevere mutation (COL4A5, 27 patients; COL4A3, 4 patients; COL4A4, 1 patient). Patient survival was similar in patients with severe and nonsevere mutations (89% vs. 84% at 5 years, 83% vs. 75% at 10, 15, and 20 years; P = 0.46). Graft survival was not affected by the severity of mutation (77% vs. 63% at 5 years, 60% vs. 55% at 10 years, 55% vs. 55% at 15 years, and 55% vs. 50% at 20 years; P = 0.65). Clinically significant anti-GBM glomerulonephritis occurred in 1 male patient with severe COL4A5 mutation 6 years after transplantation recurred in a subsequent graft, leading twice to graft loss. Conclusion:Although severe mutations affect the severity of AS, they do not have an impact on patient and graft survival after transplantation. De novo anti-GBM nephritis after transplantation was less frequent than previously reported, occurring in only 1.4% of AS patients, and in 2% of males with COL4A5 mutation.
| S-EPMC5976824 | biostudies-literature
Project description:Mutations in the COL4A5 gene cause X-linked Alport syndrome (XLAS). Understanding the correlation between clinical manifestations and the underlying mutations adds prognostic value to genetic testing, which is increasingly available. Our aim was to determine the association between genotype and phenotype in 681 affected male participants with XLAS from 175 US families. Hearing loss and ocular changes were present in 67 and 30% of participants, respectively. Average age of participants at onset of ESRD was 37 years for those with missense mutations, 28 years for those with splice-site mutations, and 25 years for those with truncating mutations (P < 0.0001). We demonstrated a strong relationship between mutation position and age at onset of ESRD, with younger age at onset of ESRD associated with mutations at the 5' end of the gene (hazard ratio 0.766 [95% confidence interval 0.694 to 0.846] per 1000 bp toward the 3' end; P < 0.0001). Affected participants with splice mutations or truncating mutations each had two-fold greater odds of developing eye problems than those with missense mutations; development of hearing impairment showed a similar trend. Hearing loss and ocular changes associated with mutations located closer to the 5; end of the gene. These strong genotype-phenotype correlations could potentially help in the evaluation and counseling of US families with XLAS.
| S-EPMC2865738 | biostudies-literature
Project description:Alport syndrome is an inherited disorder of basement membrane collagen IV that frequently results in end-stage renal disease. Patients with Alport syndrome who undergo renal transplantation have generally excellent outcomes. Posttransplant antiglomerular basement membrane nephritis is a rare complication of renal transplantation for Alport syndrome. Because Alport syndrome is a genetic disorder, potential related donors must be carefully evaluated in order to minimize harm.
| S-EPMC6198874 | biostudies-literature
Project description:ImportanceOptical coherence tomography (OCT) findings of temporal macular thinning are important in the diagnosis and prognosis of X-linked Alport syndrome (XLAS).ObjectivesTo report OCT findings and severity of temporal macular thinning in a cohort with XLAS and to correlate these and other ocular findings with mutation genotype.DesignPatients with XLAS underwent genotyping for COL4A5 mutations and complete eye examinations with retinal imaging using spectral domain OCT and fundus photography. Temporal macular thinning was calculated from OCT measurements by comparing the ratio of the retinal thickness of the temporal to the nasal subfields with a published normative database.SettingUniversity departments of ophthalmology and nephrology.ParticipantsThirty-two patients from 24 families.Main outcome and measuresTemporal thinning index calculated from spectral domain OCT scans.ResultsAll study patients had a mutation associated with the X-linked COL4A5 gene. Eleven different mutations were identified. Eleven of 32 patients (34%) expressed the L1649R mutation. Of a total of 63 eyes with available OCT scans, 44 (70%) had severe pathological temporal macular thinning. The L1649R mutation was associated with the least amount of severe temporal macular thinning and later onset of renal failure.Conclusions and relevanceTemporal macular thinning is a prominent sign associated with XLAS, suggesting that OCT measurements are essential in the diagnosis and prognosis of the disease. The L1649R mutation in the COL4A5 gene causes a relatively mild form of XLAS characterized by late-onset renal failure and less frequent, severe temporal macular thinning relative to other COL4A5 mutations. The pathological basis for the retinal abnormalities of XLAS remains to be established.
| S-EPMC3746023 | biostudies-literature
Project description:Background and objectivesX-linked Alport syndrome is caused by mutations in the COL4A5 gene. Although many COL4A5 mutations have been detected, the mutation detection rate has been unsatisfactory. Some men with X-linked Alport syndrome show a relatively mild phenotype, but molecular basis investigations have rarely been conducted to clarify the underlying mechanism.Design, setting, participants, & measurementsIn total, 152 patients with X-linked Alport syndrome who were suspected of having Alport syndrome through clinical and pathologic investigations and referred to the hospital for mutational analysis between January of 2006 and January of 2013 were genetically diagnosed. Among those patients, 22 patients had suspected splice site mutations. Transcripts are routinely examined when suspected splice site mutations for abnormal transcripts are detected; 11 of them showed expected exon skipping, but others showed aberrant splicing patterns. The mutation detection strategy had two steps: (1) genomic DNA analysis using PCR and direct sequencing and (2) mRNA analysis using RT-PCR to detect RNA processing abnormalities.ResultsSix splicing consensus site mutations resulting in aberrant splicing patterns, one exonic mutation leading to exon skipping, and four deep intronic mutations producing cryptic splice site activation were identified. Interestingly, one case produced a cryptic splice site with a single nucleotide substitution in the deep intron that led to intronic exonization containing a stop codon; however, the patient showed a clearly milder phenotype for X-linked Alport syndrome in men with a truncating mutation. mRNA extracted from the kidney showed both normal and abnormal transcripts, with the normal transcript resulting in the milder phenotype. This novel mechanism leads to mild clinical characteristics.ConclusionsThis report highlights the importance of analyzing transcripts to enhance the mutation detection rate and provides insight into genotype-phenotype correlations. This approach can clarify the cause of atypically mild phenotypes in X-linked Alport syndrome.
| S-EPMC4220764 | biostudies-literature
Project description:BackgroundAlport syndrome is an inherited renal disease caused by mutations in COL4A3, COL4A4, or COL4A5 genes. Coexisting mutations in either two of the three genes in Alport patients have been reported recently. However, the effect of heterozygous mutations in COL4A3 or COL4A4 genes in X-linked Alport syndrome (XLAS) patients is unclear.MethodsUsing targeted next-generation sequencing, six unrelated Chinese children were identified to have a combination of a pathogenic variant in COL4A5 and a heterozygous mutation in COL4A3 or COL4A4. They were three males and three females. Another three XLAS males each with only one pathogenic variant in COL4A5 were included. The clinical data were analyzed and compared between the males in two groups (group 1, males with a pathogenic variant in COL4A5 and a heterozygous pathogenic variant in COL4A3 or COL4A4; group 2, males with only one pathogenic variant in COL4A5).ResultsPatients with XLAS who also had heterozygous pathogenic COL4A3 or COL4A4 variants accounted for 1% of Alport syndrome. In this study, three children showed coexisting pathogenic variants in COL4A5 and COL4A3. Two children showed pathogenic variants in COL4A5 and COL4A4. One child had pathogenic variants in the three COL4A3-5 genes, in which the pathogenic variant in COL4A5 was de novo and the pathogenic variants in COL4A4 and COL4A3 were inherited independently (in trans). The site and type of mutations in COL4A5 were similar between the two groups. It was revealed that males in group 1 presented more severe proteinuria than males in group 2 (p < 0.05).ConclusionThe present study provides further evidence for complicated genotype in Alport syndrome. For the first time, we reported a case with three pathogenic variants in COL4A5, COL4A3, and COL4A4 genes. Moreover, we found that heterozygous pathogenic COL4A3 or COL4A4 variants are likely to make XLAS disease more serious.
| S-EPMC6503168 | biostudies-literature
Project description:Alport syndrome is an inherited chronic human kidney disease, characterized by glomerular basement membrane abnormalities. This disease is caused by mutations in COL4A3, COL4A4, or COL4A5 gene. The knockout mice for Col4α3, Col4α4, and Col4α5 are developed and well characterized for the study of Alport syndrome. However, disease progression and effects of pharmacological therapy depend on the genetic variability. This model was reliable only to mouse. In this study, we created a novel Alport syndrome rat model utilizing the rGONAD technology, which generated rat with a deletion of the Col4α5 gene. Col4α5 deficient rats showed hematuria, proteinuria, high levels of BUN, Cre, and then died at 18 to 28 weeks of age (Hemizygous mutant males). Histological and ultrastructural analyses displayed the abnormalities including parietal cell hyperplasia, mesangial sclerosis, and interstitial fibrosis. Then, we demonstrated that α3/α4/α5 (IV) and α5/α5/α6 (IV) chains of type IV collagen disrupted in Col4α5 deficient rats. Thus, Col4α5 mutant rat is a reliable candidate for the Alport syndrome model for underlying the mechanism of kidney diseases and further identifying potential therapeutic targets for human renal diseases.
| S-EPMC8531394 | biostudies-literature
Project description: Not available
| S-EPMC6609819 | biostudies-literature
Project description:BackgroundAlport 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.ObjectivesThe 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).MethodsWe 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.ResultsThe 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.ConclusionsThe 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.
| S-EPMC8613584 | biostudies-literature
Project description:Angiotensin-[1-7] (Ang-[1-7]) antagonize the actions of the renin-angiotensin-system via the Mas receptor and thereby exert renoprotective effects. Murine recombinant angiotensin-converting enzyme (ACE)2 was reported to show renoprotective effects in an experimental Alport syndrome model; however, the protective effect of direct administration of Ang-[1-7] is unknown. Here, we used Col4a3-/- mice as a model of Alport syndrome, which were treated with saline or Ang- [1-7]; saline-treated wild-type mice were used as a control group. The mice were continuously infused with saline or Ang-[1-7] (25 μg/kg/h) using osmotic mini-pumps. Col4a3-/- mice showed increased α-smooth muscle actin (SMA), collagen, and fibronectin expression levels, which were attenuated by Ang-[1-7] treatment. Moreover, Ang-[1-7] alleviated activation of transforming growth factor-β/Smad signaling, and attenuated the protein expression of ED-1 and heme oxygenase-1, indicating reduction of renal inflammation. Ang-[1-7] treatment further reduced the expression levels of inflammatory cytokines and adhesion molecules and attenuated apoptosis in human kidney cells. Finally, Ang-[1-7] downregulated TNF-α converting enzyme and upregulated ACE2 expression. Thus, treatment with Ang-[1-7] altered the ACE2-Ang-[1-7]-Mas receptor axis in the kidneys of Col4a3-/- mice to attenuate the nephropathy progression of Alport syndrome.
| S-EPMC7060323 | biostudies-literature