A related molecule, EMR2 (CD312), discovered by Lin and Stacey (64), is expressed by human myeloid cells in blood and tissues, binds chondroitin sulfate B/dermatan sulfate and has been implicated in a human genetic syndrome, vibratory urticaria (65), associated with mast cell degranulation. This evidence concerns the gene ADGRE2 and vibratory urticaria.