GM1 gangliosidosis is a lysosomal storage disorder, characterized by psychomotor deterioration, visceromegaly, facial coarseness, retinal cherry-red spots, and skeletal abnormalities. We report six unrelated patients with GM1 gangliosidosis with extensive Mongolian spots on the trunk and extremities that provided clue to clinical diagnosis. All patients exhibited psychomotor delay, coarse facies, hepatosplenomegaly, hypotonia, and dysostosis multiplex. Four patients had retinal cherry-red spots. The condition was confirmed by identification of very low activities of beta-galactosidase enzyme in peripheral leukocytes and biallelic pathogenic variants in the GLB1 gene. We identified one novel (c.1479G>T) and two known (c.75 + 2dup and c.1369C>T) pathogenic variants in homozygous state in them. Our work ascertains extensive Mongolian spots as a diagnostic handle for early recognition of GM1 gangliosidosis. Though a known feature of GM1 gangliosidosis, considerable variation in the prevalence and ethnic differences are observed. This report illustrates the Mongolian spots pictorially in Indian patients.

中文翻译：

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GM1 神经节苷脂沉积症中的蒙古斑：图片报告。

GM1 神经节苷脂贮积症是一种溶酶体贮积症，其特征是精神运动功能恶化、内脏肿大、面部粗糙、视网膜樱桃红色斑点和骨骼异常。我们报告了六名不相关的 GM1 神经节苷脂沉积症患者，躯干和四肢有广泛的蒙古斑，为临床诊断提供了线索。所有患者均表现出精神运动延迟、面部粗糙、肝脾肿大、肌张力减退和多发性骨营养不良。四名患者有视网膜樱桃红色斑点。通过鉴定外周白细胞中β-半乳糖苷酶的活性非常低和GLB1基因中的双等位基因致病变异，证实了这种情况。我们在其中鉴定了一种新的 (c.1479G>T) 和两种已知的 (c.75 + 2dup 和 c.1369C>T) 纯合状态的致病变异。我们的工作确定了广泛的蒙古斑点作为早期识别 GM1 神经节苷脂病的诊断句柄。尽管 GM1 神经节苷脂沉积症是已知的特征，但观察到患病率和种族差异的相当大的差异。这份报告以图形方式说明了印度患者的蒙古斑。