Alport Syndrome With a Rare Collagen Type IV Alpha-4 (COL4A4) Gene Mutation: A Case Report.

Alport syndrome (AS) is a rare, progressive hereditary kidney disease characterized by sensorineural hearing loss and visual abnormalities. It is caused by a mutation in the collagen type IV alpha-4 (COL4A4) gene, which produces type IV collagen, and often manifests in individuals with hematuria, proteinuria, edema, and hypertension. Here, we present a case of AS in a 15-year-old boy with a COL4A4 gene mutation, with renal and extrarenal findings. The patient presented with subnephrotic proteinuria and microscopic hematuria, autoimmune hypothyroidism, and keratoconus. Light microscopy examination of renal biopsy revealed three globally sclerosed renal cortical parenchyma areas with periglomerular fibrosis, and electron microscopy showed variable thickness of glomerular basement membrane with festooned appearance, as well as splitting of lamina densa giving basket weave and criss-cross pattern.