These Anxa1+ neurons project densely to the most dorsal striatum and serve as markers of vulnerability in PD mouse models,13–15 and in the brains of human PD patients.16 This molecular classification has enabled the development of new intersectional genetic models12,13,17 to study these otherwise intermingled SNc dopamine neuron populations, ultimately enhancing our understanding of PD mechanisms. Here, ANXA1 is linked to Parkinson disease.