Pathological diagnosis of Alport syndrome.

Alport syndrome (AS) is a hereditary nephritis characterized by structural abnormalities in the glomerular basement membrane resulting from pathogenic variants in the COL4A3, COL4A4, and COL4A5 genes. Conventional pathological evaluations reveal nonspecific light microscopic changes and diagnostic clues can be obtained through electron microscopy. Type IV collagen staining elucidates distinct patterns based on AS inheritance, aiding in subtype classification. However, limitations arise, particularly in autosomal dominant cases. Genetic testing, particularly next-generation sequencing, gains prominence due to its ability to identify diverse mutations within COL4A3, COL4A4, and COL4A5.