Molecular analysis of ADPKD has proved difficult for a long time, because of genetic and allelic heterogeneity, for the presence of GC-rich regions and more importantly because the 5′ region of PKD1, from exons 1 to 33, is duplicated in six highly homologous pseudogenes, all located in chromosome 16p7, 8. Here, PKD1 is linked to autosomal dominant polycystic kidney disease.