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Said SM, Fidler ME, Valeri AM, McCann B, Fiedler W, Cornell LD, Alexander MP, Alkhunaizi AM, Sullivan A, Cramer CH, Hogan MC, Nasr SH. Negative Staining for COL4A5 Correlates With Worse Prognosis and More Severe Ultrastructural Alterations in Males With Alport Syndrome. Kidney Int Rep 2016; 2:44-52. [PMID: 29142939 PMCID: PMC5678677 DOI: 10.1016/j.ekir.2016.09.056] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Accepted: 09/23/2016] [Indexed: 01/15/2023] Open
Abstract
Introduction Alport syndrome (AS) is a genetic disorder characterized by progressive hematuric nephropathy with or without sensorineural hearing loss and ocular lesions. Previous studies on AS included mostly children. Methods To determine the prognostic value of loss of staining for collagen type IV alpha 5 (COL4A5) and its relationship with the ultrastructural glomerular basement membrane alterations, we performed direct immunofluorescence using a mixture of fluorescein isothiocyanate-conjugated and Texas-red conjugated antibodies against COL4A5 and COL4A2, respectively, on renal biopsies of 25 males with AS (including 16 who were diagnosed in adulthood). Results All patients showed normal positive staining of glomerular basement membranes and tubular basement membranes for COL4A2. Of the 25 patients, 10 (40%) patients showed loss of staining for COL4A5 (including 89% of children and 13% of adults) and the remaining 15 (60%) had intact staining for COL4A5. Compared with patients with intact staining for COL4A5, those with loss of staining had more prominent ultrastructural glomerular basement membrane alterations and were younger at the time of biopsy. By Kaplan-Meier survival analysis and Cox regression analysis, loss of staining for COL4A5 predicted earlier progression to overt proteinuria and stage 2 chronic kidney disease or worse. By multivariate Cox regression analysis, loss of staining for COL4A5 was an independent predictor of the development of overt proteinuria and stage 2 chronic kidney disease or worse. Discussion Thus, the COL4A5 expression pattern has an important prognostic value and it correlates with the severity of ultrastructural glomerular basement membrane alterations in males with AS. Loss of COL4A5 staining is uncommon in patients with AS diagnosed in their adulthood.
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Affiliation(s)
- Samar M. Said
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Mary E. Fidler
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Anthony M. Valeri
- Division of Nephrology, Columbia University, College of Physicians and Surgeons, New York, New York, USA
| | - Brooke McCann
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Wade Fiedler
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Lynn D. Cornell
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | | | | | | | - Carl H. Cramer
- Division of Pediatric Nephrology, Mayo Clinic, Rochester, Minnesota, USA
| | - Marie C. Hogan
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Samih H. Nasr
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
- Correspondence: Samih H. Nasr, Division of Anatomic Pathology, Mayo Clinic, Hilton 10-20, 200 First Street, SW, Rochester, Minnesota 55905, USA.Division of Anatomic PathologyMayo ClinicHilton 10-20, 200 First Street, SWRochesterMinnesota 55905USA
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