Ascertainment of patients with classic severe ADPKD phenotypes can yield PKD1 variants in up to 85% of solved patients.6, 7, 8, 9 However, in general nephrology clinics where patients are referred with multiple kidney cysts but normal or near-normal kidney function, as many as one-third will have no PKD1 variant and 15% have no pathogenic variant identified.4 Here, PKD1 is linked to autosomal dominant polycystic kidney disease.