In 2018, the Radboud university medical center started the SOFIA study: SOlitary Functioning kIdney: Aetiology and prognosis. The study is aimed at children with congenital or acquired solitary functioning kidneys and has three main goals:

1) To investigate the cause of congenital solitary functioning kidney

Currently, little is known about the cause of a congenital solitary functioning kidney (SFK), but scientist think it is a multifactorial disease. This means it is due to a combination of environmental exposures, such as diseases or lifestyle of the mother during pregnancy, and genetic factors. To investigate the role of environmental factors, parents are asked to fill out a questionnaire with questions about their health and lifestyle. To investigate genetic factors, we ask for a bit of saliva from children with SFK, from which we can extract DNA to analyse.

2) To predict which children with a solitary functioning kidney are prone for renal injury

Children with SFK are now checked yearly by a doctor, despite the fact that many of these children might have a very low risk of renal injury. Therefore, we want to look at associations between certain medical conditions and childhood illnesses, such as urinary tract infections, and the risk of renal injury in children with SFK. Children with congenital and acquired SFK are both eligible for this research question. We want to predict which children have a low risk and which children have a high risk for renal injury. Again, we will gather data using a questionnaire and from extracting DNA from saliva.

3) To investigate early markers of renal injury in urine

To evaluate whether there is renal injury in children with a solitary functioning kidney, doctors currently measure blood pressure and check for protein in a urine sample. But with new techniques even smaller parts of protein, which are called peptides, can be seen and investigated. Hopefully, we can use this technique to identify renal injury in an earlier stage, so we can start treatment earlier and prevent a decline of renal function. For this research question, we do not need extra material, since we can use urine that is gathered using a regular control visit.


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