We read with interest the recent studies by Skuladottir and colleagues and Cogan and colleagues, which report a novel association between monoallelic loss-of-function (LoF) variants in the ITSN1 gene and risk for Parkinson’s disease (PD)1,2. The first study observed that heterozygous LoF variants in ITSN1 confer a large risk for developing PD in analyses combining the deCODE, UK Biobank, and Accelerating Medicines Partnership Parkinson’s Disease (AMP-PD) datasets1.
