COL4A1 variants cause a spectrum of systemic disorders encompassed by Gould syndrome. While kidney involvement is recognized, its long-term progression and detailed kidney pathology remain uncharacterized. We present a 39-year-old man with a heterozygous p.G1239R COL4A1 variant, persistent microscopic hematuria, and a progressive eGFR decline of −1.2 mL/min/1.73 m2 per year over a 10-year follow-up. Light microscopy showed only focal global glomerulosclerosis and mild tubular dilatation. Immunofluorescence for the α1 chain of type IV collagen (α1[IV]) revealed reduced signal intensity in the tubular basement membrane (TBM).