PPP1R21 encodes for a conserved protein that is involved in endosomal maturation. Biallelic pathogenic variants in PPP1R21 have been associated with a syndromic neurodevelopmental disorder from studying 13 affected individuals. In this report, we present 11 additional individuals from nine unrelated families and their clinical, radiological, and molecular findings. We identified eight different variants in PPP1R21, of which six were novel variants. Global developmental delay and hypotonia are neurological features that were observed in all individuals. There is also a similar pattern of dysmorphic features with coarse faces as a gestalt observed in several individuals. Common findings in 75% of individuals with available brain imaging include delays in myelination, wavy outline of the bodies of the lateral ventricles, and slight prominence of the bodies of the lateral ventricles. PPP1R21-related neurodevelopmental disorder is associated with a consistent phenotype and should be considered in highly consanguineous individuals presenting with developmental delay/intellectual disability along with coarse facial features.

中文翻译：

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扩大 PPP1R21 相关神经发育障碍的表型

PPP1R21编码参与内体成熟的保守蛋白。对 13 名受影响个体的研究表明， PPP1R21的双等位基因致病变异与综合征性神经发育障碍有关。在本报告中，我们介绍了来自 9 个无关家庭的另外 11 名个体及其临床、放射学和分子发现。我们在PPP1R21中发现了八种不同的变体，其中六种是新变体。整体发育迟缓和肌张力低下是在所有个体中观察到的神经学特征。在几个个体中也观察到类似的畸形特征，即面部粗糙，就像格式塔一样。 75% 具有可用脑成像的个体的常见发现包括髓鞘形成延迟、侧脑室体波状轮廓以及侧脑室体轻微突出。PPP1R21相关的神经发育障碍与一致的表型相关，对于表现出发育迟缓/智力障碍以及粗糙面部特征的高度近亲的个体应予以考虑。