Genetic analysis and in vitro validation of a case of Alport syndrome due to a splicing variant of COL4A5 gene / 中华医学遗传学杂志

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.

Penicillium marneffei infection after renal transplantation: one case report / 中华器官移植杂志

Clinical data were retrospectively reviewed for one case of penicillium marneffei infection after renal transplantation (RT) to explore a proper management of peniciliosis marneffei (PSM)transplantation.This case had a history of pulmonary tuberculosis and underwent RT due to uremia.After discharging, postoperative recovery was excellent.Recurrent cough occurred at Month 7 post-operation.Fiberoptic bronchoscopy and pulmonary CT indicated a possibility of pulmonary tuberculosis.However, a definite diagnosis of PSM was confirmed by next generation sequencing (NGS) and pathogenic bacteria culture of alveolar lavage fluid.After adjusting immunosuppressive agents and regular antifungal treatment with voriconazole, respiratory symptoms improved and pulmonary CT hinted at a resorption of lesion.Features of pulmonary CT and bronchoscopic examination were nearly similar to those of tuberculosis.Thus early bacterium culture and NGS may aid an definite diagnosis.Voriconazole is an effective treatment of the disease.