PKD2 and kidney disorder: Multiple cohorts around the world have now demonstrated a genotype-phenotype correlation with the most severe disease associated with PKD1 truncating variants, followed by PKD1 nontruncating variants and the mildest disease associated with PKD2 variants.11, 12, 13 Nonetheless, substantial variability in kidney disease severity exists for a given mutation class and individuals with PKD1 truncating mutations can still have relatively mild disease.5