What Causes Nephrotic Syndrome? Nephrotic syndrome causes your kidneys to leak heavy amounts of protein, leading to severe swelling (edema) and foamy urine. But what actually causes it? It depends on your age: In Children: Minimal Change Disease (MCD) is the most common cause and usually responds very well to treatment. In Adults: FSGS, Membranous Nephropathy, and Diabetes are the leading causes. Dr. Ahmed Ayyaz – Consultant Nephrologist 📞 For Appointment: 923134938908 🏥 Wamiq Hospital, Sahiwa