Alport syndrome complicated with steroid-sensitive nephrotic syndrome: a case report.

At 2 years and 4 months old, a girl presented with microscopic hematuria, mild edema, and nephrotic-range proteinuria with hypoalbuminemia and hypercholesterolemia without other extrarenal manifestations. She had a family history of microscopic hematuria. Kidney biopsy revealed a glomerular basal membrane of uneven thickness combined with podocytopathy. Genetic testing revealed a heterozygous c.3499G > A (p.Gly1167Arg) variant in COL4A3, which has been reported as a pathogenic variant of autosomal dominant Alport syndrome; this variant was inherited from her father. Treatment with steroids and immunosuppressants was effective. Podocytopathy should be considered in Alport syndrome patients with a young age of onset and nephrotic-range proteinuria. Electron microscopy plays an important role in diagnosis.