Despite normal STIM1 mRNA and protein expression, SOCE in PBMC isolated from P1 and P2 was severely impaired after stimulation with the sarcoplasmic/endoplasmic Ca2+ ATPase inhibitor thapsigargin (TG) compared to PBMC from the patients’ mother and a HD control (Fig 1F). Here, STIM1 is linked to Huntington disease.