Abstract:
Congenital fibrosis of the extraocular muscles (CFEOM) type 1 is associated with heterozygous missense variants in KIF21A, which encodes a kinesin-like motor protein. Individuals with CFEOM1 have severe paralysis of upgaze and ptosis, resulting in a pronounced chin-up head posture. There can also be limitations of horizontal eye movements. Loss of function of KIF26A, an unconventional kinesin motor protein that lacks ATP-dependent motor activity, has been recently reported to cause a spectrum of congenital brain malformations associated with defects in migration, localization, and growth of excitatory neurons. It has also been associated with megacolon resembling Hirschsprung\'s disease. We report the case of a boy with homozygous loss of function of KIF26A with restricted eye movements, specifically restricted upgaze and downgaze with variable nystagmus and dissociated vertical eye movements. This case represents a congenital cranial dysinnervation disorder, most similar to CFEOM, and is the first report of a congenital cranial dysinnervation disorder caused by a kinesin other than KIF21A.
摘要:
先天性眼外肌纤维化(CFEOM)1型与KIF21A中的杂合错义变异有关,编码驱动蛋白样运动蛋白。患有CFEOM1的人有严重的上凝视和上下垂瘫痪,导致明显的仰起下巴的头部姿势。还可能存在水平眼睛运动的限制。KIF26A功能丧失,一种缺乏ATP依赖性运动活性的非常规驱动蛋白,最近有报道会导致一系列与迁移缺陷相关的先天性脑畸形,本地化,和兴奋性神经元的生长。它也与类似于先天性巨结肠的疾病有关。我们报告了一例KIF26A纯合功能丧失且眼球运动受限的男孩,特别限制的上凝视和下凝视,具有可变的眼球震颤和分离的垂直眼球运动。这个病例是先天性颅骨神经支配障碍,最类似于CFEOM,并且是由KIF21A以外的驱动蛋白引起的先天性颅骨神经支配障碍的第一份报告。