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Abstract: TH-PO1001

Alport Syndrome: Phenotype-Genotype Correlation in Lithuanian Families

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Cerkauskaite, Agne, Vilnius University, Institute of Clinical medicine, Vilnius, Lithuania
  • Cerkauskiene, Rimante, Children's hospital, Vilnius University Hospital Santaros clinics, Vilnius, Lithuania, Vilnius, Lithuania
  • Miglinas, Marius, Vilnius University Hospital Santariskiu Klinikos, Vilnius, Lithuania
Background

Alport syndrome (AS) is a rare inherited collagen IV nephropathy, caused by mutation in COL4 genes leading to progressive kidney injury with extrarenal manifestations including ocular and hearing abnormalities. Exact incidence of AS is not well known due to clinical and genetic heterogeneity of the disease. The diagnosis of AS is confirmed by a pathogenic mutation in the COL4A5 gene, associated with X-linked AS or pathogenic mutations in COL4A3 or COL4A4 genes inherited in autosomal pattern.

Methods

Data analysis of the clinical, histological and genetic records of the patients with suspected AS was made. Inclusion criteria were associated with a high grade suspicion for AS such as positive family history, hematuria as an early sign of the disease, progressive chronic kidney disease (CKD), sensorineural hearing loss and several ocular abnormalities.

Results

87 patients with suspected Alport syndrome (23 children and 64 adults), 51 females and 36 males were included. 33 patients were suggested to have Alport syndrome due to specific renal biopsy findings. Other patients had positive family history. Diagnosis of AS was genetically confirmed in 74 % patients, with COL4A3, COL4A4 and COL4A5 genes 82 %, 8%, 10% respectively. In total 20 different familial mutations were found. All patients had hematuria. Progressing chronic kidney disease was seen in 39 % of the patients with an average age at diagnosis 15,4 years (14 – 40 y), whereas 36 % patients with CKD had end-stage renal disease and underwent on dialysis. CKD was significantly more frequent and more numerous in COL4A5 comparing with COL4A3 and COL4A4 genes mutations. Disease progression correlated with the age (p<0.05). Hearing abnormalities were presented in 22,4 % of all AS cases. Ocular abnormalities and vision alterations were seen in 18,4 % patients and were strongly associated with COL4A5 gene mutations.

Conclusion

COL4A5 mutations cause more severe phenotypic manifestation in male patients, specially related with a more severe renal phenotype while mutations in COL4A3 or COL4A4 are related with autosomal AS with milder clinical alterations. Further epidemiological studies are needed for better understanding of AS manifestations.