enlarged kidney in my 6 yr old

My 6 yr. daughter has had blood (hematuria)  and protein (proteinuria) in her urine.  Her urine was as dark as Dr. Pepper.  Her pediatrician ordered an ultra sound.  Today the results show that her left kidney is large and the right kidney is within normal limits, however toward the upper limit of normal for size.  There is no hydronephrosis.  She still has proteins and blood in her urine.  The pediatrician is sending her to a specialist.  I would like an idea of what type of disorder this could be.  My oldest daughter and I have a history of kidney stones.  There were no remarks about this on the ultrasound report.