Q. A 6-year-old boy with no significant past medical history was admitted yesterday through the emergency department. The patient presented with a two-week history of bilateral leg swelling and weight gain of 4 kg (8.8 lb) over the same period of time. He also complained of foamy urine and mild fatigue. There was no history of recent travel, no known sick contacts, and his immunizations are up to date. On admission, the patient was found to have generalized edema, particularly in the lower extremities. No rashes or lesions were noted. Vital signs were within normal limits, as were visual and auditory evaluations. Initial laboratory results demonstrated a serum albumin level of 2.1 g/dL, an elevated urine protein-to-creatinine ratio of 10, and a cholesterol level of 300 mg/dL. His complete blood count and chemistry panel was within normal limits. The patient was admitted for further diagnostic testing. He has done well overnight, with vital signs remaining within normal limits and no new complaints. Laboratory results this morning reveals a proteinuria of 5 g/day, normal immunoglobulin levels including IgA, test for both ANCA and ANA were negative, as was an anti-dsDNA assay. Based on the information you have at this time, what is the most likely diagnosis?