Hernandez-Castillo C R, Diaz R, Rezende T J R, Adanyeguh I, Harding I H, Mochel F, Fernandez-Ruiz J
From the Faculty of Computer Science (C.R.H.-C.), Dalhousie University, Halifax, Nova Scotia, Canada.
Physiology Department, Faculty of Medicine (R.D., J.F.-R.), Universidad Nacional Autónoma de México, Cuidad de Mexico, Mexico.
AJNR Am J Neuroradiol. 2021 Sep;42(9):1735-1739. doi: 10.3174/ajnr.A7202. Epub 2021 Jul 1.
Spinocerebellar ataxia type 7 is an autosomal dominant neurodegenerative disease caused by a cytosine-adenine-guanine (CAG) repeat expansion. Clinically, spinocerebellar ataxia type 7 is characterized by progressive cerebellar ataxia, pyramidal signs, and macular degeneration. In vivo MR imaging studies have shown extensive gray matter degeneration in the cerebellum and, to a lesser extent, in a range of cortical cerebral areas. The purpose of this study was to evaluate the impact of the disease in the spinal cord and its relationship with the patient's impairment.
Using a semiautomated procedure applied to MR imaging data, we analyzed spinal cord area and eccentricity in a cohort of 48 patients with spinocerebellar ataxia type 7 and compared them with matched healthy controls. The motor impairment in the patient group was evaluated using the Scale for Assessment and Rating of Ataxia.
Our analysis showed a significantly smaller cord area ( = 9.04, < .001, = 1.31) and greater eccentricity ( = -2.25, =. 02, = 0.32) in the patient group. Similarly, smaller cord area was significantly correlated with a greater Scale for Assessment and Rating of Ataxia score ( = -0.44, = .001). A multiple regression model showed that the spinal cord area was strongly associated with longer CAG repetition expansions (= .002) and greater disease duration (= .020).
Our findings indicate that cervical spinal cord changes are progressive and clinically relevant features of spinocerebellar ataxia type 7, and future investigation of these measures as candidate biomarkers is warranted.
7型脊髓小脑共济失调是一种由胞嘧啶-腺嘌呤-鸟嘌呤（CAG）重复序列扩增引起的常染色体显性神经退行性疾病。临床上，7型脊髓小脑共济失调的特征为进行性小脑共济失调、锥体束征和黄斑变性。活体磁共振成像研究显示，小脑存在广泛的灰质变性，在一定程度上，一系列大脑皮质区域也有灰质变性。本研究的目的是评估该疾病对脊髓的影响及其与患者损伤的关系。
我们采用一种应用于磁共振成像数据的半自动程序，分析了48例7型脊髓小脑共济失调患者的脊髓面积和偏心率，并将其与匹配的健康对照进行比较。使用共济失调评估与评分量表对患者组的运动损伤进行评估。
我们的分析显示，患者组的脊髓面积显著更小（t = 9.04，P <.001，效应量d = 1.31），偏心率更大（t = -2.25，P =.02，效应量d = 0.32）。同样，较小的脊髓面积与更高的共济失调评估与评分量表得分显著相关（r = -0.44，P =.001）。多元回归模型显示，脊髓面积与更长的CAG重复序列扩增显著相关（P =.002），且与更长的病程显著相关（P =.020）。
我们的研究结果表明，颈髓改变是7型脊髓小脑共济失调的渐进性且具有临床相关性的特征，因此有必要进一步研究将这些指标作为候选生物标志物。
