CD200 and Hashimoto thyroiditis: Even more recently, germline alleles near genes encoding the CD200 immune checkpoint—specifically, CD200, CD200R1 that encodes the receptor for CD200, and DOK2 that encodes a downstream adapter protein—were found to have significant associations with, but opposite effects on, autoimmune hypothyroidism, asthma and eczema versus basal cell carcinoma risks, recapitulating the pattern of pleiotropy observed at the CTLA4 genomic locus [6].