By reanalyzing single-nucleus RNA sequencing data from postmortem Parkinson’s disease (PD) brains, we found that a BAM subset characterized by CD169 (SIGLEC1) expression is significantly reduced in PD patients compared with healthy controls (Prashant et al., 2024; Sun and Jiang, 2024; Yeo et al., 2022). The gene discussed is SIGLEC1; the disease is Parkinson disease.