The choice of KR depends on age, individual production, and brain sensitivity to ketone bodies (2–4): in clinical practice the KR may differ from 2,5–4:1 since the treatment with cKD in patients with GLUT1-DS is lifelong, so clinicians aim to reduce the amount of fat to a level without symptoms (seizures, paroxymal exercise-induced dyskinesia, lack of energy) and a level of ketosis within the recommended range. This evidence concerns the gene SLC2A1 and chronic kidney disease.