In this work, we investigated the mRNA levels of both the housekeeping-expressed plasma membrane-associated PMCA1 isoform [34–35] and the sarco-endoplasmic reticulum-associated (SERCA2 and SERCA3) pumps in PBMCs from manifest and pre-manifest HD patients compared to sex- and age-matched controls. The gene discussed is ATP2A3; the disease is Huntington disease.