Definition of Minimal change disease:

Minimal change disease is a kidney disorder that can lead to nephrotic syndrome, although the nephrons of the kidney look normal under a regular microscope.

Causes, incidence, and risk factors:

Each kidney is made of more than a million units called nephrons, which filter blood and produce urine.

In minimal change disease, there is damage to the glomeruli -- the tiny blood vessels inside the nephron. The disease gets its name because this damage isn't visible under a regular microscope. It can only be seen under an electron microscope.

Minimal change disease is the most common cause of nephrotic syndrome in children. It is also frequently seen in adults.

The cause is unknown, but the disease may occur after:

• Allergic reactions
• Recent immunizations
• Viral infection