Abstract: TH-PO492
Alport Syndrome in Iceland: Epidemiology and Outcomes
Session Information
- Genetic Kidney Diseases: Genotypes and Phenotypes in Cases
October 24, 2024 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1202 Genetic Diseases of the Kidneys: Non-Cystic
Authors
- Ingadóttir, Saga, School of Health Sciences, University of Iceland, Reykjavik, Iceland
- Indridason, Olafur S., Landspitali, Reykjavik, Capital, Iceland
- Valdimarsson, Sindri, Landspitali, Reykjavik, Iceland
- Thorsteinsdottir, Hjordis, Domus barnalaeknar, Reykjavik, Iceland
- Edvardsson, Vidar O., Landspitali, Reykjavik, Iceland
Background
Alport syndrome (AS) is caused by mutations in the collagen IV genes, COL4A3, COL4A4 and COL4A5. Three types of AS have been described: X-linked AS (XLAS), autosomal recessive AS (ARAS) and autosomal dominant AS (ADAS). The aim of this study was to examine the epidemiology and outcomes of AS in Iceland.
Methods
This was a retrospective study of all Icelandic AS cases in the period 1968-2023. Affected individuals were identified through diagnosis codes, the Icelandic Renal Registry, and family tracing. Medical records were reviewed for the confirmation of diagnosis. End-stage kidney disease (ESKD) was defined as the need for kidney replacement therapy. Clinical characteristics, family history and genetic testing were used for the diagnosis of X-linked AS. The diagnosis of autosomal AS was made in individuals with persistent haematuria in whom a secondary cause had been excluded.
Results
We identified 76 individuals with AS, 52 with XLAS (13 males) and 24 individuals with autosomal AS (8 males). Diagnosis was confirmed with genetic testing in 45 of the 52 XLAS patients and in 2 autosomal AS cases. The mean (±SD) age at XLAS diagnosis was 28.5±22.3 years and 9.4±9.6 years for autosomal AS. The prevalence of AS in January 2024 was 17.7 per 100,000 population. The average yearly incidence of XLAS in the last 10 years was 0.54 individuals per 100,000 population. Five autosomal AS patients (20.8%) had some degree of proteinuria at latest follow-up, but all had normal kidney function. A total of 10 individuals with XLAS developed ESKD, 7 men and 3 women, at the median (range) age of 19 (16-25) and 60 (37-69) years for males and females, respectively.
Conclusion
The prevalence of AS in Iceland appears to be similar to other western countries. A high proportion of males but only a few females with XLAS progress to ESKD. The outcomes of individuals with autosomal AS are excellent.
Funding
- Government Support – Non-U.S.