Fig. 8: Cartoon of hypothetical mechanism of PKAN neuronal death.

The alteration of endosomal trafficking due to CoA deficiency leads to inefficient iron transport to mitochondria and cytosolic iron excess. Subsequent neurodegeneration occurs by excitotoxicity and aberrant release of toxic amounts of gliotransmitters, such as glutamate (2), or by ferroptosis (3), from reactive astrocytes. Treatment with CoA rescues CoA deficiency-associated impairment of endosomal trafficking (4), thus impeding iron overload and neuronal death.