Background: Skew deviation is typically caused by brainstem damage, and has not been identified with focal cerebellar lesions. This vertical strabismus has been attributed to asymmetric disruption of vestibuloocular r...Background: Skew deviation is typically caused by brainstem damage, and has not been identified with focal cerebellar lesions. This vertical strabismus has been attributed to asymmetric disruption of vestibuloocular reflex (VOR) projections from otolithic receptors of the utricle to ocular motoneurons, but asymmetry of the utriculo-ocular counter-roll reflex has not been detected. Methods: Lesions localized to the cerebellum were identified by MRI in five patients with vertical strabismus. Their skew deviation was measured by prism cover tests in all patients and by search coils in three patients. The angular VOR was tested in patients and 10 controls during sinusoidal ± 10 degree torsional, vertical, and horizontal head-on-body rotations at 0.5, 1, and 2 Hz. Static torsional VOR gain was measured by the change in torsional eye position divided by change in head position during maintained head tilt. Results: Static torsional VOR gains were asymmetric in each patient. Three patterns of asymmetry were identified: 1) decreased static gain in one eye in both directions; 2) decreased gains in both eyes in one direction; and 3) asymmetric gain in one direction in one eye alone. Dynamic torsional VOR gains were symmetrically reduced in both directions in both eyes in all patients. Conclusions: Focal cerebellar lesions can cause skew deviation. The static torsional vestibuloocular reflex (VOR) is linked to cerebellar control of vertical vergence. Asymmetry between the eyes or in direction of the static torsional VOR provides evidence that monocular or binocular imbalance of the utriculo-ocular reflex leads to cerebellar skew deviation.展开更多
目的探讨RFC1(replication factor C subunit 1)基因突变导致伴周围神经病和前庭反射消失的小脑性共济失调综合征(CANVAS)患者的临床及遗传学特点,以提高对该疾病的认识。方法报道2021年1月就诊于北京大学第三医院的1例CANVAS患者。从...目的探讨RFC1(replication factor C subunit 1)基因突变导致伴周围神经病和前庭反射消失的小脑性共济失调综合征(CANVAS)患者的临床及遗传学特点,以提高对该疾病的认识。方法报道2021年1月就诊于北京大学第三医院的1例CANVAS患者。从患者外周血提取DNA进行详细的共济失调相关遗传学检测。检索文献中已报道的RFC1基因变异导致的CANVAS,总结分析所有患者的临床及遗传学特点。结果本例患者为51岁女性,主要表现为进行性加重的步态不稳,结合辅助检查符合CANVAS临床诊断。患者基因检测结果除外已报道的其他遗传性共济失调变异,同时完善RFC1基因检测,结果显示患者存在双等位基因致病性变异结构(AAGGG)exp重复扩增。检索国内外报道RFC1基因变异导致CANVAS的文献共14篇,整体CANVAS患者RFC1基因变异率为68%~100%,散发及家族性CANVAS患者中RFC1基因变异率不同,该基因变异具有种族差异。结论成人起病的晚发型共济失调患者中,通过头颅磁共振联合电生理及前庭功能检查有利于CANVAS的识别,RFC1基因检测对于该病诊断有重要意义。本例CANVAS患者扩大了我国共济失调的疾病谱,证实了RFC1基因突变在中国人群共济失调筛查中具有重要意义。展开更多
文摘Background: Skew deviation is typically caused by brainstem damage, and has not been identified with focal cerebellar lesions. This vertical strabismus has been attributed to asymmetric disruption of vestibuloocular reflex (VOR) projections from otolithic receptors of the utricle to ocular motoneurons, but asymmetry of the utriculo-ocular counter-roll reflex has not been detected. Methods: Lesions localized to the cerebellum were identified by MRI in five patients with vertical strabismus. Their skew deviation was measured by prism cover tests in all patients and by search coils in three patients. The angular VOR was tested in patients and 10 controls during sinusoidal ± 10 degree torsional, vertical, and horizontal head-on-body rotations at 0.5, 1, and 2 Hz. Static torsional VOR gain was measured by the change in torsional eye position divided by change in head position during maintained head tilt. Results: Static torsional VOR gains were asymmetric in each patient. Three patterns of asymmetry were identified: 1) decreased static gain in one eye in both directions; 2) decreased gains in both eyes in one direction; and 3) asymmetric gain in one direction in one eye alone. Dynamic torsional VOR gains were symmetrically reduced in both directions in both eyes in all patients. Conclusions: Focal cerebellar lesions can cause skew deviation. The static torsional vestibuloocular reflex (VOR) is linked to cerebellar control of vertical vergence. Asymmetry between the eyes or in direction of the static torsional VOR provides evidence that monocular or binocular imbalance of the utriculo-ocular reflex leads to cerebellar skew deviation.
文摘目的探讨RFC1(replication factor C subunit 1)基因突变导致伴周围神经病和前庭反射消失的小脑性共济失调综合征(CANVAS)患者的临床及遗传学特点,以提高对该疾病的认识。方法报道2021年1月就诊于北京大学第三医院的1例CANVAS患者。从患者外周血提取DNA进行详细的共济失调相关遗传学检测。检索文献中已报道的RFC1基因变异导致的CANVAS,总结分析所有患者的临床及遗传学特点。结果本例患者为51岁女性,主要表现为进行性加重的步态不稳,结合辅助检查符合CANVAS临床诊断。患者基因检测结果除外已报道的其他遗传性共济失调变异,同时完善RFC1基因检测,结果显示患者存在双等位基因致病性变异结构(AAGGG)exp重复扩增。检索国内外报道RFC1基因变异导致CANVAS的文献共14篇,整体CANVAS患者RFC1基因变异率为68%~100%,散发及家族性CANVAS患者中RFC1基因变异率不同,该基因变异具有种族差异。结论成人起病的晚发型共济失调患者中,通过头颅磁共振联合电生理及前庭功能检查有利于CANVAS的识别,RFC1基因检测对于该病诊断有重要意义。本例CANVAS患者扩大了我国共济失调的疾病谱,证实了RFC1基因突变在中国人群共济失调筛查中具有重要意义。
