In contrast, cerebrospinal fluid (CSF) volume showed a significant increase in the full penetrance group (≥40 CAG repeats) compared to the normal repeat group (≤26 CAG repeats), with a highly significant p value (*** p < 0.00001).
Although variations in mean volumes were observed among groups with different numbers of CAG repeats (≤26, 27–35, and ≥40), these differences did not reach statistical significance in any of the regions analyzed.
In studies of cerebellar atrophy, no correlation has been found with CAG repeat [ 46 , 47 ], and there is a nonsignificant trend toward an inverse correlation between cerebellar atrophy and disease duration, given that cerebellar neuronal loss occurs later in the clinical course of the disease [ 48 ].