LRRK2 and Parkinson disease: Similarly, aberrant synaptic vesicular trafficking is also evident in other forms of early‐onset parkinsonism, including LRRK2,27, 28VMAT2,29 and SNCA‐related disease.30 Clathrin‐mediated endocytosis is crucial for the regulation of developmental signaling pathways through internalization of receptors or ligands and is required for axon and dendrite outgrowth.31 Presence of developmental delay well before onset of parkinsonism in patients with DNAJC6 mutations further corroborates the notion that auxilin is likely to have a central role in neurodevelopment, given its role in CME.