Legius syndrome is a disorder of the RAS and mitogen‐activated protein kinase (MAPK) pathway first described in 2007 by Eric Legius, et al., that has been considered a milder phenotype than reported in the RASopathy neurofibromatosis type 1 (NF1). However, with approximately 200 cases reported in the literature, the Legius syndrome phenotype remains to be fully characterized. We report a child who presented with moyamoya syndrome and who has Legius syndrome due to a pathogenic variant in SPRED1. Vascular complications such as moyamoya syndrome have been reported in NF1. However, this association has not been reported in Legius syndrome. This child’s case may represent an expansion of the clinical phenotype of Legius syndrome, and further study is needed. We emphasize the importance of obtaining neuroimaging studies in patients with Legius syndrome who present with new neurologic deficits.

中文翻译：

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Legius综合征患儿的Moyamoya综合征：将脑血管病变引入SPRED1表型吗？

Legius综合征是RAS和有丝分裂原激活蛋白激酶（MAPK）通路的一种疾病，由Eric Legius等人于2007年首次描述，该表型被认为比RAS病1型神经纤维瘤病（NF1）报道的表型温和。然而，在文献中报道了大约200例病例，Legius综合征的表型仍有待充分表征。我们报告谁与烟雾综合征和谁拥有Legius综合征呈现一个孩子由于病原变异在SPRED1。NF1中已报道了诸如moyamoya综合征等血管并发症。但是，在Legius综合征中尚未报道这种关联。这个孩子的情况可能代表了Legius综合征临床表型的扩大，需要进一步的研究。我们强调在出现新的神经功能缺损的Legius综合征患者中进行神经成像研究的重要性。