Since healthy relatives of the VUR probands are not reliable negative controls for VUR , we used a population of 90 race-matched , healthy individuals , unrelated to the VUR patients , as controls to perform an association study .
O O O O O B-DiseaseOrPhenotypicFeature O O O O O O O B-DiseaseOrPhenotypicFeature O O O O O O O O O O O O O O O B-DiseaseOrPhenotypicFeature B-OrganismTaxon O O O O O O O O O