Department of Obstetrics and Gynecology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu Province, China; Department of Obstetrics and Gynecology, Nanjing GaoChun People's Hospital, Nanjing 211300, Jiangsu Province, China.
Clinical Center of Reproductive Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu Province, China.
Bone. 2021 Dec;153:116169. doi: 10.1016/j.bone.2021.116169. Epub 2021 Sep 4.
Skeletal dysplasia caused by genetic mutations places a heavy burden on families and society. This study was performed to precise diagnosis of variants of unknown significance and to expand the genotypic spectrum of lethal skeletal dysplasia.
According to the ultrasonic phenotype of the proband and whole-exome sequencing results, variation sites or genes that may be related to the disease were screened out. We verified the accuracy of the variation site through Sanger sequencing. Using bioinformatics, zebrafish models, and assisted reproduction technology (ART) combined with preimplantation genetic testing for monogenic diseases, the disease-causing mutation was verified.
A missense mutation (c.3944G>A, p.Cys1315Tyr) was found in the coding region of COL2A1. Although the mutation is a variant of unknown significance, it is highly conserved and was predicted to be harmful by the SIFT and PolyPhen-2 software. In contrast to the control group, col2a1a mutation-expressing zebrafish larvae showed significant spinal curvature. Through preimplantation genetic testing for monogenic diseases excluding the missense mutation, a child conceived by ART was birthed with normal bone development.
We identified a de novo mutation in human COL2A1 related to lethal skeletal dysplasia and expanded the mutation spectrum of type II collagenopathies. In addition, we provided a new strategy based on a zebrafish model and ART for patients who harbour variants of unknown significance to have a healthy baby without genetic disease similar to the proband.
遗传突变导致的骨骼发育不良给家庭和社会带来了沉重的负担。本研究旨在对意义不明的变异进行精确诊断,并扩展致死性骨骼发育不良的基因型谱。
根据先证者的超声表型和全外显子测序结果,筛选出可能与疾病相关的变异位点或基因。我们通过 Sanger 测序验证了变异位点的准确性。利用生物信息学、斑马鱼模型和辅助生殖技术(ART)结合单基因疾病的植入前遗传学检测,验证了致病突变。
在 COL2A1 的编码区发现了一个错义突变(c.3944G>A,p.Cys1315Tyr)。尽管该突变是意义不明的变异,但它高度保守,SIFT 和 PolyPhen-2 软件预测其具有有害性。与对照组相比,col2a1a 突变表达的斑马鱼幼虫表现出明显的脊柱弯曲。通过排除错义突变的单基因疾病植入前遗传学检测,通过 ART 受孕的婴儿出生时骨骼发育正常。
我们鉴定了一个与致死性骨骼发育不良相关的 COL2A1 中的新生突变,并扩展了 II 型胶原病的突变谱。此外,我们基于斑马鱼模型和 ART 为携带意义不明变异的患者提供了一种新策略,使他们能够拥有一个与先证者相似的无遗传疾病的健康婴儿。