Clinical Genetics Unit, Department of Women's and Children's Health, University of Padova, Padova, Italy.
Laboratorio di Genetica ed Epidemiologia Clinica, Instituto di Ricerca Pediatrica Citta della Speranza, Padova, Italy.
J Med Genet. 2021 Aug;58(8):526-533. doi: 10.1136/jmedgenet-2020-106833. Epub 2020 Aug 3.
Dysfunction in non-motile cilia is associated with a broad spectrum of developmental disorders characterised by clinical heterogeneity. While over 100 genes have been associated with primary ciliopathies, with wide phenotypic overlap, some patients still lack a molecular diagnosis.
To investigate and functionally characterise the molecular cause of a malformation disorder observed in two sibling fetuses characterised by microphthalmia, cleft lip and palate, and brain anomalies.
A trio-based whole exome sequencing (WES) strategy was used to identify candidate variants in the gene. In silico, in vitro and in vivo () studies were carried out to explore the impact of mutations on protein structure and function, and relevant biological processes.
encodes a member of the Crescerin1 family of proteins regulating microtubule dynamics. Its orthologue in , , is expressed in a subset of sensory neurons and localises in the dendritic cilium where it is required for chemosensation. Nematode lines harbouring the corresponding missense variant in were generated by CRISPR/Cas9 technology. Although chemotaxis ability on a NaCl gradient was not affected, point mutants displayed impaired lipophilic dye uptake, with shorter and altered cilia in sensory neurons. Finally, in vitro analysis of microtubule polymerisation in the presence of wild-type or mutant TOG2 domain revealed a faster polymerisation associated with the mutant protein, suggesting aberrant tubulin binding.
Our data are in favour of a causative role of variants in the pathogenesis of this novel disorder, connecting this gene with primary ciliopathy.
非动力纤毛功能障碍与多种发育障碍有关，这些障碍的特点是临床异质性。虽然已经有超过 100 个基因与原发性纤毛病相关，表现型广泛重叠，但仍有一些患者缺乏分子诊断。
研究并对两例同胞胎儿畸形综合征的分子病因进行功能特征分析，这两例胎儿表现为小眼球、唇腭裂和脑异常。
采用基于三核苷酸的全外显子组测序（WES）策略，鉴定候选基因中的变异。通过计算机模拟、体外和体内研究，探讨突变对蛋白结构和功能以及相关生物学过程的影响。
该基因编码一种微管动力学调节蛋白 Crescerin1 家族的成员。在秀丽隐杆线虫中，其同源基因 表达于一组感觉神经元中，并定位于树突纤毛，该基因在化学感应中起作用。通过 CRISPR/Cas9 技术在线虫中生成了携带相应错义突变的品系。尽管在氯化钠梯度上的趋化能力没有受到影响，但 点突变显示出脂溶性染料摄取减少，感觉神经元中的纤毛变短且形态异常。最后，在存在野生型或突变 TOG2 结构域的体外微管聚合分析中，发现突变蛋白与更快的聚合相关，提示异常的微管结合。
我们的数据支持 变异在该新型疾病发病机制中的致病作用，将该基因与原发性纤毛病联系起来。
