A 7-year-old boy has been receiving treatment for a month. At the time of hospitalization, he had marked edemas, proteinuria of 7.1 g/L, and daily urine protein of 4.2 g. Biochemical blood test has shown persistent hypoproteinemia (43.2 g/L) and hypercholesterolemia (9.2 mmol/L ). What leading glomerulonephritis syndrome is most likely in this patient?