Objective: To describe the evolution of chorea severity over time in individuals with Huntington disease (HD) stratified by Total Functional Capacity (TFC).

Background: Chorea is the most common motor symptom in adult-onset HD. Chorea negatively affects quality of life (QoL) and overall functional capacity in individuals with HD.¹ Addressing troublesome chorea in HD is crucial to reduce the burden of motor symptomatology in HD. Historically, chorea has been reported to increase initially, plateau, and decrease over time, however there is limited longitudinal data assessing chorea severity by disease stage.²

Method: Participants were adults aged ≥18 years from Enroll-HD, a global, longitudinal, observational study for individuals with or at risk for HD (data cut 2013 – 31 October 2020). Participants in the manifest population were grouped into TFC categories determined by TFC score (according to the Shoulson and Fahn staging system) at their baseline visit (TFC score 7–‍13/Stage 1–‍2 [early], 3–‍6/Stage 3 [middle], 0–‍2/Stage 4–‍5 [late]).³ Chorea severity was assessed by Total Maximal Chorea (TMC) score which was recorded at baseline and at annual visits. Patients with at least 4 years of follow-up were selected to estimate chorea progression over time.

Results: Participants were grouped by HD stage (early, n=7441; middle, n=2330; late, n=1120). At baseline, mean (SD) TMC scores increased as HD stage progressed (early, 8.0 [ 4.7]; middle, 10.4 [5.8]; late, 10.6 [6.9]). Among participants with ≥4 years of follow-up (n=1271), there was a slight increase in TMC over time. Chorea severity (mean [SD] TMC score) increased over time for participants with early-stage HD (Years [Y] 1-2, 8.5 [5.0]; Y 2-3, 9.1 [5.3]; Y 3-4, 9.5 [5.6]), but TMC scores plateaued at high levels in middle (Y 1-2, 10.6 [5.3]; Y 2-3, 10.6 [6.0]; Y 3-4, 10.1 [5.7]) and late-stage HD (Y 1-2, 10.4 [6.6]; Y 2-3, 9.8 [6.9]; Y 3-4, 9.7 [6.2]).

Conclusion: An increase in chorea severity was seen in early-stage HD. Chorea severity plateaued in middle- and late-stage HD, however, importantly, chorea did not decrease longitudinally in any stage of HD. These results support the need for increased awareness about the potential for persistent chorea in late-stage HD. Future work is necessary to better determine the impact chorea has on patient QoL and functional capacity in advanced HD.

References: 1. Thorley EM, Iyer RG, Wicks P, et al. Understanding how chorea affects health-related quality of life in Huntington disease: an online survey of patients and caregivers in the United States. Patient. 2018;11(5):547-559. doi:10.1007/s40271-018-0312-x
2. Young AB, Shoulson I, Penney JB, et al. Huntington’s disease in Venezuela: neurologic features and functional decline. Neurology. 1986;36(2):244-249. doi:10.1212/wnl.36.2.244
3. Shoulson, I., & Fahn, S. (1979). Huntington disease: clinical care and evaluation. Neurology. 29(1):1–3. https://doi.org/10.1212/wnl.29.1.1

« Back to 2022 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/chorea-severity-change-over-time-in-huntington-disease-and-by-huntington-disease-stage/