Nephrotic syndrome is the most common glomerular disease in children. There is wide variation in the incidence of nephrotic syndrome in different populations, with a higher incidence in children of South Asian descent. However, nephrotic syndrome with a more indolent course and poor prognosis is more common in African American children. The disparity in the prevalence and severity of nephrotic syndrome is likely due to complex interactions between environmental and biological factors. Recent advances in genome science are providing insight into some of the biological factors that may explain these disparities.