Various stimuli result in the activation and degranulation of mast cells, releasing a large amount of trypsin and tryptase (TRY), which, in turn, activate protease-activated receptor 2 (PAR2) on nociceptive neurons, causing neuronal excitement and releasing nociceptive neurotransmitters CGRP and SP, ultimately increasing VH in patients with FD [8]. The gene discussed is F2RL1; the disease is Fabry disease.