This was a national, cross-sectional study recruiting patients from nephrology out-patient clinics and dialysis units. All patients between 18 and 70 years of age who were on follow up in outpatient clinic and dialysis unit at the Istanbul Medical Faculty from October 2009 to October 2015 were included in the study. All patients and healthy controls enrolled in this study gave informed consent to participate in the survey. They were all asked to answer a questionnaire including socio-demographic data, history of familial kidney disease and consanguineous marriage. Additional information was obtained from their private physicians and medical files. To ensure reliability of administration of the questionnaire, all interviewers underwent training using a standardized protocol.
