Abstract: FR-PO614
A Case of Autosomal Dominant Alport Syndrome Diagnosed by a Second Renal Biopsy
Session Information
- Trainee Case Reports - IV
October 26, 2018 | Location: Exhibit Hall, San Diego Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Trainee Case Reports
- 1002 Genetic Diseases of the Kidney: Non-Cystic
Authors
- Asakawa, Tomohiko, Suwa Central Hospital, Chino, NAGANO, Japan
- Nozu, Kandai, Kobe University, Kobe, Japan
- Araki, Makoto, Suwa Central Hospital, Chino, NAGANO, Japan
Introduction
Typically, Alport syndrome is diagnosed by a renal biopsy and is characterized by Alport symptoms, including kidney disease, hearing loss, and eye abnormalities. However, symptoms and signs are characteristic of X-linked Alport syndrome that are not applicable to the autosomal dominant condition.
Case Description
A male patient experienced asymptomatic hematuria since childhood. His mother had chronic hemodialysis because of unknown renal disease. He received a renal biopsy at the age of 16 years; however, light and electron microscopic findings revealed minor abnormalities and the immunofluorescence staining of type IV collagen α5 chain was normal. Since then, he received conservative treatment ; however, hematuria and proteinuria tended to increase over time. Therefore, he received a second renal biopsy at the age of 23 years. While light microscopy revealed focal glomerulosclerosis in some glomeruli, electron microscopy revealed irregular thickening and thinning with a reticulated change in the glomerular basement membrane. Although renal biopsy findings suggested Alport syndrome, he reported no hearing loss or visual impairment. Therefore, genetic analysis revealed a single-base deletion of type IV collagen a3 chain [exon26 c.1826delC, p(Pro 609Leufs*138)], which, along with a family history, confirmed the diagnosis of autosomal dominant Alport syndrome. Currently, the patient is receiving conservative treatment, including renin–angiotensin system inhibitors.
Discussion
A renal biopsy cannot diagnose Alport syndrome at an early stage because of an unclear change in the basement membrane. Besides, autosomal dominant Alport syndrome lacks eyes and ears abnormalities, which delays the diagnosis unless positive suspicion. Recent advancements in sequence technology have revealed autosomal dominant Alport syndrome to be a relatively frequent disorder (19%–31% of Alport syndrome cases). Thus, in patients with family history of renal impairment, we should consider the possibility of autosomal dominant Alport syndrome, even if absence of Alport symptom except hematuria.