Abstract:

Objective　Through molecular genetic diagnosis of a child with Noonan syndrome, this study explored the pathogenesis of gene mutations, prenatal screening, and genetic diagnosis. Methods　Second generation high-throughput sequencing was applied to the child with Noonan syndrome in Altay Maternal and Child Health Hospital, and Sanger sequencing was used to validate the child and their parents. Results　The sequencing results of the child's genes suggested the presence of a heterozygous mutation in the MRAS gene, which was a guanine G mutation at nucleotide 68 to thymine T (c.68G>T), resulting in a mutation of amino acid 23 from Glycine to Valine (p.Gly23Val). Conclusion　According to the American College of Medical Genetics and Genomics (ACMG) variant classification guidelines, this variant is a pathogenic variant, and high-throughput sequencing is helpful for the diagnosis of this complex genetic disease.

Key words:

Noonan syndrome, Mutation, MRAS gene

摘要：

目的　通过对1例Noonan综合征儿童进行分子遗传学诊断，探讨其基因突变的发病机制及产前筛查和基因诊断。方法　对阿勒泰地区妇幼保健院1例Noonan综合征儿童应用二代高通量测序，采用Sanger测序对患儿及其父母进行验证。结果　患儿基因测序结果提示MRAS基因存在杂合突变，该杂合突变为68号核苷酸的鸟嘌呤G突变为胸腺嘧啶T（c.68G>T），从而导致第23号氨基酸由甘氨酸突变为缬氨酸（p.Gly23Val）。结论　根据美国医学遗传学与基因组学学会（ACMG）变异分类指南，该变异为致病性变异，高通量测序有助于该类复杂遗传病的诊断。

关键词:

Noonan综合征, 突变, MRAS基因