DMD and Norrie disease: However, the ion-gated potassium channel functionality was disturbed in DMD astrocytes, in line with previous reports that found an association of inwardly rectifying potassium channel (Kir4.1) with dystrophin, via the α-syntrophin linker protein49,50(Fig. 1h); representative current trace for ND and DMD/D2 is shown in Fig. S3B (i)-(ii).