Programa de Pós-graduação em Odontologia, Faculdade de Farmácia, Odontologia e Enfermagem, Universidade Federal do Ceará, Fortaleza, CE, Brasil.
Center for Precision Environmental Health, Departments of Molecular and Cellular Biology, Molecular and Human Genetics and Medicine, Baylor College of Medicine, Houston, TX, USA.
Braz J Med Biol Res. 2021 Sep 24;54(11):e11396. doi: 10.1590/1414-431X2021e11396. eCollection 2021.
Current understanding of the genetic factors contributing to the etiology of non-syndromic craniosynostosis (NSC) remains scarce. The present work investigated the presence of variants in ALX4, EFNA4, and TWIST1 genes in children with NSC to verify if variants within these genes may contribute to the occurrence of these abnormal phenotypes. A total of 101 children (aged 45.07±40.94 months) with NSC participated in this cross-sectional study. Parents and siblings of the probands were invited to participate. Medical and family history of craniosynostosis were documented. Biological samples were collected to obtain genomic DNA. Coding exons of human TWIST1, ALX4, and EFNA4 genes were amplified by polymerase chain reaction and Sanger sequenced. Five missense variants were identified in ALX4 in children with bilateral coronal, sagittal, and metopic synostosis. A de novo ALX4 variant, c.799G>A: p.Ala267Thr, was identified in a proband with sagittal synostosis. Three missense variants were identified in the EFNA4 gene in children with metopic and sagittal synostosis. A TWIST1 variant occurred in a child with unilateral coronal synostosis. Variants were predicted to be among the 0.1% (TWIST1, c.380C>A: p. Ala127Glu) and 1% (ALX4, c.769C>T: p.Arg257Cys, c.799G>A: p.Ala267Thr, c.929G>A: p.Gly310Asp; EFNA4, c.178C>T: p.His60Tyr, C.283A>G: p.Lys95Glu, c.349C>A: Pro117Thr) most deleterious variants in the human genome. With the exception of ALX4, c.799G>A: p.Ala267Thr, all other variants were present in at least one non-affected family member, suggesting incomplete penetrance. Thus, these variants may contribute to the development of craniosynostosis, and should not be discarded as potential candidate genes in the diagnosis of this condition.
目前，对于导致非综合征性颅缝早闭（NSC）的遗传因素的了解仍然很少。本研究旨在调查 ALX4、EFNA4 和 TWIST1 基因中的变异是否存在于 NSC 患儿中，以验证这些基因内的变异是否可能导致这些异常表型的发生。共有 101 名 NSC 患儿（年龄 45.07±40.94 个月）参与了这项横断面研究。邀请了先证者的父母和兄弟姐妹参加。记录了颅缝早闭的医疗和家族史。采集生物样本以获得基因组 DNA。通过聚合酶链反应和 Sanger 测序扩增人类 TWIST1、ALX4 和 EFNA4 基因的编码外显子。在双侧冠状、矢状和额状颅缝早闭的患儿中发现了 ALX4 中的 5 个错义变异。在一名矢状颅缝早闭的先证者中发现了一个新的 ALX4 变异，c.799G>A：p.Ala267Thr。在患有额状和矢状颅缝早闭的患儿中发现了 EFNA4 基因中的 3 个错义变异。一名单侧冠状颅缝早闭的患儿出现了 TWIST1 变异。变异被预测为人类基因组中 0.1%（TWIST1，c.380C>A：p.Ala127Glu）和 1%（ALX4，c.769C>T：p.Arg257Cys，c.799G>A：p.Ala267Thr，c.929G>A：p.Gly310Asp；EFNA4，c.178C>T：p.His60Tyr，C.283A>G：p.Lys95Glu，c.349C>A：Pro117Thr）最具破坏性的变异之一。除了 ALX4，c.799G>A：p.Ala267Thr 外，所有其他变异都存在于至少一名非受累家族成员中，提示不完全外显率。因此，这些变异可能导致颅缝早闭的发生，不应将其排除在该疾病诊断的潜在候选基因之外。
