Demographics and characteristics. HDGECs = Huntington ́s disease gene-expansion carriers, N = Number of participants, SD = standard deviation, UHDRS-TMS = Unified Huntington ́s Disease Rating Scale – Total Motor Score, PDGFR-β = platelet-derived growth factor receptor-β, Q-Alb = cerebrospinal fluid/plasma albumin quotient, IQR = interquartile range. Here, PDGFRB is linked to juvenile Huntington disease.