Category: Huntington's Disease
Objective: To establish the relationship between the number of CAG repetitions and the total Montreal Cognitive Assessment (MoCA) scores in patients with Huntington disease (HD).
Background: HD is an autosomal dominant neurodegenerative disorder, caused by excessive expansion of CAG triplets. With 40 or more repetitions, disease debut with neuropsychiatric disorders. Cognitive impairment in HD is characterized by dysfunction in visuospatial abilities, executive function and recognition of facial expression; with previous appearance to Frank motor signs. There is a need to detect these changes early. MoCA is a tool with high specificity and sensitivity to detect mild cognitive impairment.
Method: An observational, inferential, cross-sectional and retrospective study was carried out. With a population of 36 subjects of both sexes with clinical and molecular diagnosis of HD, they were evaluated using MoCA test. Statistical analysis was descriptive in each variable. Categorical variables were analyzed by frequency and continuous variables by means of central tendency and dispersion indices. Association and correlation between variables were sought. Finally, comparison between groups was performed using non-parametric tests.
Results: We analyzed 36 patients, 23 men (63.9%) and 13 women (33.1%). Age comparison in both genders was significantly lower in men (p = 0.016). Number of repetitions (mean = 47.7) and MoCA (mean = 21.7). A correlation matrix was performed, showing the age of onset being significant (mean= 33.9) with the number of repetitions (p = 0.006). MoCA score was not related to the number of repetitions (p = 0.723) as opposed to the evolution time (p = 0.001). The association between schooling and the onset of the disease (p = 0.004) with an earlier onset in subjects with greater schooling.
Conclusion: The number of repetitions shows no association with the MoCA score, probably due to a variation in the time of disease evolution between each patient. In our population, there is a higher prevalence of HD in men, with a lower age of onset. The MoCA average score is staged as mild dementia and the age of onset is similar to reported in the literature.
To cite this abstract in AMA style:
D. Gasca-Saldaña, A. Vega-Rosas, G. Palma-Cordero, O. Castellanos-Maya. Association between the number of CAG repetitions and cognitive performance in Huntington’s disease in patients of the National Institute of Neurology and Neurosurgery “MVS” [abstract]. Mov Disord. 2020; 35 (suppl 1). https://www.mdsabstracts.org/abstract/association-between-the-number-of-cag-repetitions-and-cognitive-performance-in-huntingtons-disease-in-patients-of-the-national-institute-of-neurology-and-neurosurgery-mvs/. Accessed June 15, 2025.« Back to MDS Virtual Congress 2020
MDS Abstracts - https://www.mdsabstracts.org/abstract/association-between-the-number-of-cag-repetitions-and-cognitive-performance-in-huntingtons-disease-in-patients-of-the-national-institute-of-neurology-and-neurosurgery-mvs/