Yu et al. further conducted trans-ethnic fine-mapping of the MHC region and discovered that HLA-DRB1*04 subtypes (HLA-DRB1 alleles with His13) may have a protective role in the development of PD by reducing the binding affinity to α-synuclein epitopes (Yu et al., 2021). The gene discussed is HLA-DRB1; the disease is Parkinson disease.