Abstract：
OBJECTIVE: Hypovitaminosis A is a leading cause of preventable childhood blindness, especially in developing nations. Vitamin A is a fat-soluble essential micronutrient that serves vital functions in the visual system and in regulating bone resorption. We report on a series of four children with mixed nutritional and compressive optic neuropathy and provide a review of the literature.
METHODS: A retrospective observational study of four males (ages 9-12), three with autism spectrum disorder who presented with loss of vision and multiple vitamin deficiencies including hypovitaminosis A.
RESULTS: Patients presented with unexplained visual loss or a change in visual behaviour. All patients had severely restricted diet comprising of predominantly carbohydrates. Two of the four cases demonstrated optic nerve pallor at initial presentation with marked optic atrophy developing in all patients over time. Electrophysiology available in two patients demonstrated optic nerve dysfunction with preserved retinal function. Extensive investigations revealed profound deficiency in multiple vitamins including vitamin A (<0.1-0.2 μmol/L, normal = 0.9-1.7 μmol/L). Three patients also had low vitamin B12 (90-111 pmol/L, normal = 170-800 pmol/L) with normal folate. All four cases had radiological evidence of skull base thickening indicative of low vitamin A. Genetic testing did not find any relevant pathogenic variants.
CONCLUSIONS: Hypovitaminosis A is a crucial form of nutritional deprivation that results in significant visual loss with potential hyperostosis and optic nerve compression exacerbating nutritional optic neuropathy. Additional micronutrient deficiencies usually co-exist and may contribute. Extra vigilance in vitamin replacement is required of clinicians with patients with autism who have restricted diets.
METHODS: A retrospective observational study of four males (ages 9-12), three with autism spectrum disorder who presented with loss of vision and multiple vitamin deficiencies including hypovitaminosis A.
RESULTS: Patients presented with unexplained visual loss or a change in visual behaviour. All patients had severely restricted diet comprising of predominantly carbohydrates. Two of the four cases demonstrated optic nerve pallor at initial presentation with marked optic atrophy developing in all patients over time. Electrophysiology available in two patients demonstrated optic nerve dysfunction with preserved retinal function. Extensive investigations revealed profound deficiency in multiple vitamins including vitamin A (<0.1-0.2 μmol/L, normal = 0.9-1.7 μmol/L). Three patients also had low vitamin B12 (90-111 pmol/L, normal = 170-800 pmol/L) with normal folate. All four cases had radiological evidence of skull base thickening indicative of low vitamin A. Genetic testing did not find any relevant pathogenic variants.
CONCLUSIONS: Hypovitaminosis A is a crucial form of nutritional deprivation that results in significant visual loss with potential hyperostosis and optic nerve compression exacerbating nutritional optic neuropathy. Additional micronutrient deficiencies usually co-exist and may contribute. Extra vigilance in vitamin replacement is required of clinicians with patients with autism who have restricted diets.
摘要：
目的：维生素A缺乏症是可预防的儿童失明的主要原因，尤其是在发展中国家。维生素A是一种脂溶性必需微量营养素，在视觉系统和调节骨吸收中起重要作用。我们报告了一系列4名患有混合性营养和压迫性视神经病变的儿童，并提供了文献综述。
方法：对四名男性（9-12岁）的回顾性观察研究，3例自闭症谱系障碍患者表现为视力丧失和多种维生素缺乏，包括维生素A缺乏症。
结果：患者表现为无法解释的视力丧失或视觉行为改变。所有患者均严格限制饮食，主要包含碳水化合物。四个病例中有两个在最初表现出视神经苍白，随着时间的推移，所有患者都出现明显的视神经萎缩。两名患者的电生理学表现出视神经功能障碍并保留了视网膜功能。广泛的调查显示，包括维生素A在内的多种维生素严重缺乏（<0.1-0.2μmol/L，normal=0.9-1.7μmol/L)。三名患者的维生素B12也很低（90-111pmol/L，正常=170-800pmol/L）与正常叶酸。所有四例病例都有颅底增厚的放射学证据，表明维生素A低。遗传检测未发现任何相关的致病变异。
结论：维生素A缺乏症是一种关键的营养剥夺形式，可导致明显的视力丧失，并伴有潜在的骨肥厚和视神经压迫，加剧了营养性视神经病变。额外的微量营养素缺乏通常共存，并可能造成。限制饮食的自闭症患者的临床医生需要格外警惕维生素替代。
方法：对四名男性（9-12岁）的回顾性观察研究，3例自闭症谱系障碍患者表现为视力丧失和多种维生素缺乏，包括维生素A缺乏症。
结果：患者表现为无法解释的视力丧失或视觉行为改变。所有患者均严格限制饮食，主要包含碳水化合物。四个病例中有两个在最初表现出视神经苍白，随着时间的推移，所有患者都出现明显的视神经萎缩。两名患者的电生理学表现出视神经功能障碍并保留了视网膜功能。广泛的调查显示，包括维生素A在内的多种维生素严重缺乏（<0.1-0.2μmol/L，normal=0.9-1.7μmol/L)。三名患者的维生素B12也很低（90-111pmol/L，正常=170-800pmol/L）与正常叶酸。所有四例病例都有颅底增厚的放射学证据，表明维生素A低。遗传检测未发现任何相关的致病变异。
结论：维生素A缺乏症是一种关键的营养剥夺形式，可导致明显的视力丧失，并伴有潜在的骨肥厚和视神经压迫，加剧了营养性视神经病变。额外的微量营养素缺乏通常共存，并可能造成。限制饮食的自闭症患者的临床医生需要格外警惕维生素替代。
