ADCK4-related glomerulopathy is a recently recognized clinical entity associated with insidious onset in young children and a high potential to progress to chronic kidney disease in adolescents. Early initiation of exogenous coenzyme Q10 (CoQ10) supplementation in the asymptomatic period could be protective on renal functions. In the present study, we aimed to investigate long-term follow-up of patients that we have diagnosed during the asymptomatic period and in whom we started CoQ10 treatment. We analyzed long-term effects of CoQ10 on proteinuria and estimated glomerular filtration rate (eGFR) in this patient population. A total of 8 patients (4 female, 4 male) from 6 different families were included. The mean age at diagnosis and at last visit were 16.8 +/- 11.2 years and 20.7 +/- 11.7 years, respectively. None of the patients had extrarenal system involvement. At the time of initiation of treatment; median eGFR was 107.8 ml/min/1.73 m(2), median proteinuria was 1008 mg/m(2)/day. After a median follow-up period of 25.3 +/- 5.8 months, median proteinuria decreased to 318.5 mg/m(2)/day (p=0.03) and median eGFR remained stable at 99.6 ml/min/1.73 m(2) (p=0.21). Coenzyme Q10 treatment is effective for reducing proteinuria and seems to be renoprotective.