额外标记染色体所致过度生长综合征一个家系的遗传学分析

Genetic analysis of a Chinese pedigree affected with overgrowth syndrome due to a small supernumerary marker chromosome

目的应用多种遗传学检测技术对1个额外标记染色体(sSMC)所致过度生长综合征家系进行遗传学分析,明确其致病原因,探讨sSMC的起源及重组形式。方法选取2021年8月31日于嘉兴市妇幼保健院就诊的1个过度生长综合征家系为研究对象,应用染色体核型分析、单核苷酸多态性微阵列(SNP array)及荧光原位杂交(FISH)技术,对该家系各成员进行染色体鉴定。结果结合染色体核型分析、SNP array及FISH检测结果,先证者及其妹妹的核型为47,XX,+neo(15)(qter→q25.3:)mat,其母亲的核型为47,XX,del(15)(q25.3:),+neo(15)(qter→q25.3:),其父亲的核型未见异常。结论联合多种遗传学检测技术可鉴定sSMC的来源,为遗传咨询提供可靠的依据。

Objective To carry out genetic analysis for a Chinese pedigree affected with intellectual disability and overgrowth due to a supernumerary marker chromosome(sSMC).Methods A pedigree which had presented at Jiaxing Maternity and Child Health Care Hospital on August 31,2021 was selected as the study subject,for which chromosomal karyotyping,single nucleotide polymorphism-based microarray(SNP-array),and fluorescence in situ hybridization(FISH)were carried out in combination.Results SNP-array analysis showed that the proband and his sister had both harbored a 16.1 Mb duplication which encompassed the critical region of 15q26 overgrowth syndrome.FISH confirmed that the proband was 47,XX,+neo(15)(qter→q25.3:)mat,her mother was 47,XX,del(15)(q25.3:),+neo(15)(qter→q25.3:),whilst her father was normal.Conclusion Application of multiple genetic techniques has facilitated delineation of the origin of sSMC and reliable genetic counseling for this pedigree.