Cobalamin C (cblC) defect is the most common inherited disorder of cobalamin metabolism. Developmental delay, behavioral problems, and maculopathy are common, but they have not been systematically investigated. The aim of this study was to define early neurodevelopment in cblC patients and the possible contribution of different factors, such as mode of diagnosis, age at diagnosis, presence of brain lesions and epilepsy. Children up to the age of 4 years with a visual acuity ≥1/10 were evaluated using the Griffiths' Mental Development Scales. Eighteen children were enrolled (age range 12-48 months). Four were diagnosed by newborn screening (NBS); in the others mean age at diagnosis was 3.5 months (range 0.3-18 months). Eight had seizures: three in the first year, and five after the second year of life. Fourteen had brain lesions on magnetic resonance imaging (MRI). Neurovisual assessment evidenced low visual acuity (<3/10) in 4/18. NBS diagnosed patients had higher general and subquotients neurodevelopmental scores, normal brain MRI, and no epilepsy. The others showed a progressive reduction of the developmental quotient with age and language impairment, which was evident after 24 months of age. Our findings showed a progressive neurodevelopmental deterioration and a specific fall in language development after 24 months in cblC defect. The presence of brain lesions and epilepsy was associated with a worst neurodevelopmental outcome. NBS, avoiding major disease-related events and allowing an earlier treatment initiation, appeared to have a protective effect on the development of brain lesions and to promote a more favorable neurodevelopment.

中文翻译：

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钴胺素C /缺陷儿童的早期神经发育特征。

钴胺素C（cblC）缺陷是钴胺素代谢最常见的遗传性疾病。发育迟缓，行为问题和黄斑病很常见，但尚未对其进行系统的研究。这项研究的目的是确定cblC患者的早期神经发育以及不同因素的可能贡献，例如诊断方式，诊断年龄，脑病变和癫痫的存在。使用格里菲思精神发育量表对4岁以下视力≥1/10的儿童进行评估。18名儿童入组（年龄12-48个月）。新生儿筛查（NBS）诊断出四例；在其他人中，诊断时的平均年龄为3.5个月（范围0.3-18个月）。八例癫痫发作：第一年三例，第二年后五例。十四名患者在磁共振成像（MRI）上出现了脑部病变。神经视觉评估显示4/18的视力低（<3/10）。经NBS确诊的患者的神经发育分数和亚分值较高，脑部MRI正常，无癫痫病。其他人则表现出随着年龄和语言障碍的发展商逐渐减少，这在24个月大以后就很明显。我们的研究结果显示，在cblC缺损24个月后，神经发育逐渐恶化，语言发育出现特定下降。脑损伤和癫痫的存在与最差的神经发育结果有关。NBS避免了与重大疾病相关的事件并允许较早地开始治疗，似乎对脑损伤的发展具有保护作用，并促进了更有利的神经发育。