STIM1 and Myalgia: Interestingly, patients with substitution of the arginine at residue 304 by the less hydrophobic glutamine (STIM1-R304Q, another constitutively active form of STIM1) rather than tryptophan (STIM1-R304W) manifest a milder and lesser deleterious clinical phenotype of Stormorken syndrome, such as muscle weakness, myalgia, muscle stiffness, and contractures [4,9,10].