After starting our patient recruitment by sending out invitations halfway August, we received more than 100 registrations already. Many of these participants filled out the questionnaire and collected saliva, so we can truly state that we began with a flying start. We are very grateful to these participants for their cooperation.

In the last weeks, we also came into contact with many of our fellow paediatricians and paediatric nephrologists throughout the Netherlands. Most of them are enthusiastic to work with us, and are more than happy to contribute to what should become the largest cohort of children with a solitary functioning kidney in the world. Our aim is to include at least 600 patients, to acquire sufficient power to study relevant environmental and genetic risk factors.

In the coming months, we hope that we can continue to inform patients with a solitary functioning kidney about our project, so we can celebrate the 600^th inclusion within a year after starting the study!