Variation in Human Nephron Number and Association with Disease

The number of nephrons in a single human kidney without overt disease ranges over a wide range, from approximately 200,000 to more than 2.7 million. Human birth weight is directly associated with higher nephron endowment, and accordingly much of the variation in adult human nephron number is present at birth. Whereas many animal studies have investigated the associations between low nephron number, adult blood pressure, and kidney disease, relatively few studies have been conducted in humans. However, available data suggest that lower nephron number in humans, at least in some populations, is associated with higher blood pressure and increased renal pathology. Until now, estimation of nephron number has required access to whole kidneys at autopsy. Recent reports of using magnetic resonance imaging to image, count, and size glomeruli in whole kidneys suggest that the noninvasive estimation of nephron number is close at hand.