Bilateral multicystic dysplastic kidney (BMCK) is a condition in which both kidneys are replaced by multiple cysts. It is a congenital disorder that is present at birth and is caused by abnormal development of the kidneys in the womb. It is the most common cause of kidney failure in infants and can lead to long-term health problems. Symptoms may include high blood pressure, poor growth, and urinary tract infections. Treatment may include medications, dialysis, or a kidney transplant.