Park E, et al. – This study planned to gauge the focal segmental glomerulosclerosis and medullary nephrocalcinosis in children with AarF domain containing kinase 4 gene (ADCK4) mutations. Data suggested considering ADCK4 mutations in older children presenting with steroid resistant focal segmental glomerulosclerosis (FSGS). Because the condition was treatable with coenzyme Q10 (CoQ10) supplementation at an early stage, an early diagnosis of ADCK4 mutations was essential. In addition, the association with medullary nephrocalcinosis appeared as an additional diagnostic indicator.