Objective:To investigate long-term auditory changes and characteristics of Alport syndrome（AS） patients with different degrees of renal injury. Methods:Retrospectively analyzing clinical data of patients diagnosed AS from January 2007 to September 2022, including renal pathology, genetic detection and hearing examination. A long-term follow-up focusing on hearing and renal function was conducted. Results:This study included 70 AS patients, of which 33（25 males, 8 females, aged 3.4-27.8 years） were followed up, resulting in a loss rate of 52.9%.The follow-up period ranged from 1.1to 15.8 years, with 16 patients followed-up for over 10 years. During the follow-up, 10 patients presenting with hearing abnormalities at the time of diagnosis of AS had progressive hearing loss, and 3 patients with new hearing abnormalities were followed up, which appeared at 5-6 years of disease course. All of which were sensorineural deafness. While only 3 patients with hearing abnormalities among 13 patients received hearing aid intervention. Of these patients,7 developed end-stage renal disease（ESRD）, predominantly males （6/7）. The rate of long-term hearing loss was significantly different between ESRD group and non-ESRD group（P=0.013）. There was no correlation between the progression of renal disease and long-term hearing level（P>0.05）. kidney biopsies from 28 patients revealed varying degrees of podocyte lesion and uneven thickness of basement membrane. The severity of podocyte lesion was correlated with the rate of long-term hearing loss（P=0.048）, and there was no correlation with the severity of hearing loss（P>0.05）. Among 11 cases, theCOL4A5mutationwas most common （8 out of 11）, but there was no significant correlation between the mutation type and hearing phenotype（P>0.05）. Conclusion:AS patients exhibit progressive hearing loss with significant heterogeneity over the long-term.. THearing loss is more likely to occur 5-6 years into the disease course. Hearing abnormalities are closely related to renal disease status, kidney tissue pathology, and gene mutations, emphasizing the need for vigilant long-term hearing follow-up and early intervention.
Male ; Child ; Female ; Humans ; Nephritis, Hereditary/pathology* ; Retrospective Studies ; Kidney ; Deafness ; Hearing Loss/genetics* ; Kidney Failure, Chronic/pathology* ; Mutation

OBJECTIVES: To investigate the genotypes of the pathogenic gene COL4A5 and the characteristics of clinical phenotypes in children with Alport syndrome (AS). METHODS: A retrospective analysis was performed for the genetic testing results and clinical data of 19 AS children with COL4A5 gene mutations. RESULTS: Among the 19 children with AS caused by COL4A5 gene mutations, 1 (5%) carried a new mutation of the COL4A5 gene, i.e., c.3372A>G(p.P1124=) and presented with AS coexisting with IgA vasculitis nephritis; 3 children (16%) had large fragment deletion of the COL4A5 gene, among whom 2 children (case 7 had a new mutation site of loss51-53) had gross hematuria and albuminuria at the onset, and 1 child (case 13 had a new mutation site of loss3-53) only had microscopic hematuria, while the other 15 children (79%) had common clinical phenotypes of AS, among whom 7 carried new mutations of the COL4A5 gene. Among all 19 children, 3 children (16%) who carried COL4A5 gene mutations also had COL4A4 gene mutations, and 1 child (5%) had COL4A3 gene mutations. Among these children with double gene mutations, 2 had gross hematuria and proteinuria at the onset. CONCLUSIONS This study expands the genotype and phenotype spectrums of the pathogenic gene COL4A5 for AS. Children with large fragment deletion of the COL4A5 gene or double gene mutations of COL4A5 with COL4A3 or COL4A4 tend to have more serious clinical manifestations.
Humans ; Nephritis, Hereditary/pathology* ; Hematuria/complications* ; Retrospective Studies ; Collagen Type IV/genetics* ; Genotype ; Mutation

Humans ; Nephritis, Hereditary/genetics* ; Astigmatism ; Mutation ; Collagen Type IV/genetics*

OBJECTIVE: To analyze the clinical phenotype and genetic characteristics of a patient with Alport syndrome. METHODS: A patient with Alport syndrome who had visited the First Affiliated Hospital of Zhengzhou University in November 2020 was selected as the study subject. Clinical data of the patient were collected. High-throughput sequencing was carried out to detect potential variant of the COL4A3, COL4A4 and COL4A5 genes, and Sanger sequencing was carried out for verification of candidate variants in the family. RESULTS: The main clinical manifestations of the patient included hematuria, proteinuria, and impaired hearing. Audiometric testing suggested symmetrical cochlear sensory neural hearing loss on both sides. Renal biopsy revealed mild mesangial proliferative glomerulonephritis. Genetic testing revealed that the patient has harbored compound heterozygous variants of the COL4A4 gene, namely c.940G>A (p.Gly314Ser) and c.3773G>A (p.Gly1258Asp), which were respectively inherited from her father and mother. Neither variant has been reported before, and were predicted to be pathogenic based on the guidelines from the American College of Medical Genetics and Genomics. CONCLUSION The c.940G>A (p.Gly314Ser) and c.3773G>A (p.Gly1258Asp) compound heterozygous variants of the COL4A4 gene probably underlay the Alport syndrome in this patient. Above finding has enriched the mutational spectrum of the COL4A4 gene.
Female ; Humans ; Nephritis, Hereditary/genetics* ; Hematuria ; Genetic Testing ; Genomics ; Hearing ; Collagen Type IV/genetics*

OBJECTIVE: To explore the genetic basis for a patient with Alport syndrome (AS) and confirm the existence of a splicing variant. METHODS: An AS patient diagnosed at the Affiliated Hospital of Inner Mongolia Medical University on January 8, 2021 for significant proteinuria and occult hematuria was selected as the study subject. Clinical data was collected. Peripheral blood samples were collected for the extraction of genomic DNA. Whole exome sequencing and Sanger sequencing were carried out to identify potential genetic variants. An in vitro experiment was also conducted to verify the abnormal mRNA splicing. Bioinformatic software was used to analyze the conservation of amino acids of the variant sites and simulate the 3D structure of the variant collagen IV protein. Immunofluorescence and immunohistochemistry were carried out on renal tissues from the patient to confirm the presence of AS kidney injury. RESULTS: The patient, a 21-year-old male, had a 24-hour urine protein of 3.53 g/24 h, which fulfilled the diagnostic criteria for proteinuria. His blood uric acid has also increased to 491 μmol/L. DNA sequencing revealed that he has harbored a c.835-9T>A splice variant of the COL4A5 gene, which was not found in either of his parents. In vitro experiment confirmed that the variant has removed 57 bp from the exon 15 of the mRNA of the COL4A5 gene. The deletion may cause loss of amino acid residues from positions 279 to 297, which in turn may affect the stability of the secondary structure of the α5 chain encoded by the COL4A5 gene. The amino acids are conserved across various species. The result of homology modeling indicated that the trimerization of Col-IV with the mutated α5 chain could be achieved, however, the 3D structure was severely distorted. The AS kidney damage was confirmed through immunofluorescence assays. Based on the guidelines from the American College of Medical Genetics and Genomics, the c.835-9T>A variant was classified as likely pathogenic (PVS1_Moderate+PS3_Moderate+PM2_Supporting+PS2+PP3+PP4). CONCLUSION The c.835-9T>A variant of the COL4A5 gene probably underlay the AS in this patient. In vitro experiment has confirmed the abnormal splicing caused by the variant. Histopathological examination of the kidney tissue has provided in vivo evidence for its pathogenicity. Above finding has expanded the mutational spectrum of the COL4A5 gene.
Humans ; Male ; Young Adult ; Amino Acids ; China ; Collagen Type IV/genetics* ; Exons ; Nephritis, Hereditary/genetics* ; RNA Splicing

OBJECTIVE: To investigate the clinical features and genetic variant of a child with X-linked dominant Alport syndrome (XLAS). METHODS: A child who had presented at the First Affiliated Hospital of Zhengzhou University in May 2019 was selected as the study subject. Clinical data of the child was collected. Next generation sequencing (NGS) was carried out for the child. Candidate variants were validated by Sanger sequencing of his family members. RESULTS: The child, a 12-year-old boy, had mainly manifested gross hematuria, proteinuria, nephrotic syndrome, and progressive renal impairment in conjunct with hearing loss. Kidney biopsy has revealed uneven glomerular basement membrane thickness. DNA sequencing revealed that the child and his mother have both carried a heterozygous c.2632G>A (p.G878R) variant of the COL4A5 gene, for which his father and brother were of the wild type. This variant was unreported previously. Based on the guidelines from the American College of Medical Genetics and Genomics, the variant was classified as pathogenic (PS1+PM1+PM2_Supporting+PP3). CONCLUSION The maternally derived hemizygous c.2632G>A (p.G878R) variant of the COL4A5 gene probably underlay the XLAS in this child. Above finding has enriched the mutational spectrum of the COL4A5 gene.
Male ; Female ; Humans ; Child ; Nephritis, Hereditary/genetics* ; Deafness ; Kidney Glomerulus ; Genomics ; Mothers

OBJECTIVE: To analysis variants of COL4A5 gene in two Chinese pedigrees affected with Alport syndrome (AS) and provide prenatal diagnosis for them. METHODS: Two unrelated ethnic Han Chinese pedigrees who had visited the First Affiliated Hospital of Zhengzhou University respectively in September 2018 and January 2020 were selected as the study subjects. Clinical data were collected, and genomic DNA was extracted from peripheral venous blood and amniotic fluid samples for genetic testing. Following next generation sequencing, candidate variants of the COL4A5 gene were verified by Sanger sequencing and bioinformatic analysis. The gender of the fetuses was determined by the presence of sex-determining region on Y (SRY). RESULTS: Genetic testing revealed that the proband and a fetus from pedigree 1 had both harbored a c.2723G>A (p.Gly908Glu) variant in exon 32 of the COL4A5 gene, whilst the proband and a fetus from pedigree 2 had both harbored a c.3817G>A (p.Gly1273Asp) variant in exon 44 of the COL4A5 gene. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were classified as likely pathogenic (PP2+PM2_Supporting). Following exclusion of maternal contamination, PCR amplification of the SRY region indicated that both fetuses were males. CONCLUSION The c.2723G>A (p.Gly908Glu) and c.3817G>A (p.Gly1273Asp) variants of the COL4A5 gene probably underlay the AS in the two pedigrees. Detection of the SRY region can reliably identify the fetal sex, which is conducive to the prenatal diagnosis. Above results have also enriched the mutational spectrum of the COL4A5 gene and provided a reference for correlating the genotype and phenotype of the AS.
Female ; Humans ; Male ; Pregnancy ; Collagen Type IV/genetics* ; East Asian People ; Genetic Testing ; Nephritis, Hereditary/genetics* ; Pedigree ; Prenatal Diagnosis

OBJECTIVE: To explore the genetic basis for two Chinese pedigrees affected with Alport syndrome. METHODS: Potential variants of the COL4A5 gene were screened by next generation sequencing (NGS). Candidate variants were verified by Sanger sequencing of other members from the pedigrees as well as 100 healthy controls. ClustalX 2.1 win was used to analyze the conservation of amino acid sequences. SWISS-MODEL was used for assessing the influence of variations on the protein structure. RESULTS: Two heterozygous missense variants of the COL4A5 gene, namely c.2210G>A (p.Gly737Asp) and c.3799G>A (p.Gly1267Ser), were respectively identified in the affected individuals from the two pedigrees but not among the 100 healthy controls. Neither variant was reported previously. CONCLUSION The c.2210G>A (p.Gly737Asp) and c.3799G>A (p.Gly1267Ser) variants of the COL4A5 gene probably underlay the Alport syndrome in these pedigrees. Above finding has enriched the spectrum of COL4A5 gene variants and provided a basis for genetic counseling and prenatal diagnosis for the families.
Pregnancy ; Female ; Humans ; Nephritis, Hereditary/genetics* ; Pedigree ; Collagen Type IV/genetics* ; Mutation ; China

Collagen Type IV/genetics* ; Genetic Testing ; Humans ; Nephritis, Hereditary/therapy*

OBJECTIVE: To explore the genetic basis for a Chinese pedigree affected with X-linked hereditary Alport syndrome. METHODS: Next generation sequencing was carried out for the pedigree. Candidate variant was validated by Sanger sequencing. Pathological changes of renal basement membrane and expression of COL4A5 protein were analyzed by renal biopsy and immunofluorescence assay, respectively. RESULTS: All patients from the pedigree manifested progressive renal damage, gross hematuria, proteinuria and nephrotic syndrome. Renal biopsy of the proband revealed thickening of the basement membrane. No expression of the COL4A5 gene was detected by immunofluorescence. High-throughput sequencing and Sanger sequencing indicated that the proband has carried a c.3706delC (p.1236Pfs*69) variant in exon 41 of the COL4A5 gene. The same variant was also found in his mother and two brothers whom were similarly affected. CONCLUSION The novel c.3706delC (p.1236Pfs*69) variant of the COL4A5 gene probably underlay the pathogenesis of X-linked hereditary Alport syndrome in this pedigree. Above findings have enriched the spectrum of COL4A5 gene variants and provided a basis for the diagnosis and genetic counseling for the pedigree.
Collagen Type IV/genetics* ; Hematuria ; High-Throughput Nucleotide Sequencing ; Humans ; Male ; Mutation ; Nephritis, Hereditary/genetics* ; Pedigree