SYNJ1 and Parkinson disease: This is consistent with ITSN1’s established role as a multivalent scaffold protein that organizes endocytic protein interaction networks to promote clathrin-mediated endocytosis and synaptic vesicle recycling.24 Interestingly, ITSN1 appears to interact with Synaptojanin-1 (SYNJ1), which is associated with early-onset PD.