LEONARD STERN, MD: Well, the kidney consists of many parts. One of them is called the glomerulus, which is the main filtering part of the kidney. This illness attacks the glomerulus, the filtering function of the kidney. There are two forms. One is an inflammatory form, and one is a relatively bland form. They both produce the injury to the filtering part of the kidney where protein leaks into the urine, and the consequences of protein leaking into the urine over time is that the protein acts as a toxin which injures the remaining parts of the nephrons. So this, once it's initiated, is progressive and indolent in some patients, rapid in others, but will eventually result in kidney failure requiring dialysis or transplant.
LISA CLARK: People may actually know a little bit about this because two pro basketball players were recently diagnosed with FSGS -- Alonso Mourning and Sean Elliott. When you have a big-name celebrity who is diagnosed with a disease, does that immediately lead to a lot more interest and study on the disease?
JAI RADHAKRISHNAN, MD: It's usual, but as nephrologists, we see this every day. It's nothing unusual for us. That I'll tell you.
LISA CLARK: How common is it?
JAI RADHAKRISHNAN, MD: If you look at diseases that cause kidney failure, it's not common, but when you look at kidneys that cause protein to be leaked to the urine, it is probably one of the most common diagnoses that you can find in what we call nephrotic syndrome, which is a syndrome where you lose a lot of protein, you swell up, and the protein in your blood drops. It's probably the most common cause of nephrotic syndrome in certain populations.
LISA CLARK: Len, who is most at risk for developing this disease?
