A 78 y/o man with malaise presents with the following labora…

A 78 y/o man with malaise presents with the following laboratory data. Additionally his urine shows amino aciduria and phosphaturia. Oliguria is not present. A renal biopsy was performed. Images (LM, IF and EM) are shown. What is the best diagnosis?  Test Patient result Reference interval Serum albumin 4.5 g/dL 3.5-5.0 BUN, serum 18 mg/dL 9-25 Creatinine, serum 1.5 mg/dL 0.5-1.2 Fasting serum glucose 85 mg/dL 70-99 Hemoglobin A1c 5.0%