(4) In family 18477, a pregnancy was interrupted after sonographic detection of renal cysts and PKD1 analysis revealed two variants: p.(Arg459Pro), transmitted by the affected father, and p.(Gly1185Asp), present in the mother, who had no renal cysts; a healthy child was born from a second pregnancy and he was found to carry the p.(Gly1185Asp) only. This evidence concerns the gene PKD1 and cystic kidney disease.