Table 6.

Impact of CAG expansion on infratentorial structure volumes: This table illustrates the impact of CAG triplet expansion on the volumes of infratentorial structures, including the left/ right cerebellar white/gray matter and brainstem, in individuals at risk of developing Huntington’s disease. The participants are categorized based on the number of CAG repeats: ≤26 (normal), 27–35 (intermediate), and >40 (full penetrance).

Structures	Substructures	CAG	N	Average Range	Mean	Standard Deviation	Minimum	Maximum	Kruskal–Wallis H Test	p
Infratentorial structures	White matter, left cerebellum	≤26	28	17.04	12.7117	1.72630	8.92	15.60	4.551	0.103
		27–35	2	33.00
		≥40	6	20.50
	White matter, right cerebellum	≤26	28	16.95	12.3500	1.61168	8.74	15.30	4.607	0.100
		27–35	2	32.75
		≥40	6	21.00
	Gray matter, left cerebellum	≤26	28	17.00	53.575	6.9595	42.2	75.1	4.397	0.111
		27–35	2	32.50
		≥40	6	20.83
	Gray matter, right cerebellum	≤26	28	16.96	52.783	6.8373	42.3	73.4	3.732	0.155
		27–35	2	30.50
		≥40	6	21.67
	Brainstem	≤26	28	17.79	20.197	2.3384	15.6	24.9	2.421	0.298
		27–35	2	29.75
		≥40	6	18.08

Note: For the analysis of brain volumes and triplet expansion, the following statistical tests were used: Kolmogorov–Smirnov method, Student’s t-test, two-way analysis of variance with Bonferroni post hoc test, and Spearman’s test. The p values show no statistically significant differences. Source: own elaboration.