一种罕见小额外标记染色体的鉴定及临床意义分析

Genetic diagnosis and analysis of a rare small supernumerary marker chromosome

对一出生表现为缺血缺氧性脑病患者进行了遗传学诊断和病因分析。运用MRI技术对患儿脑部进行检查,运用常规G显带核型分析技术对患儿及其父母染色体核型进行分析,运用染色体芯片分析技术(CMA)对患儿及其父母全基因组进行染色体拷贝数变异分析,对多余染色体进行鉴定及定位。MRI检测结果支持患儿缺血缺氧性脑病诊断,并发现Dandy-Walker畸形表现。核型分析结果显示患儿母亲染色体核型为46,XX,t(10;13)(p11.1;q11)^([11])/46,XX^([19])。患儿父亲染色体核型结果正常。患儿染色体核型为47,XX,+mar。患儿父母CMA检测结果显示不存在200 kb以上拷贝数变异(CNVs)。患儿CMA检测结果显示10号染色体p15.3p11.1区域发生了3拷贝重复,片段大小为38.39 Mb。该研究发现一罕见10号染色体小额外标记染色体(sSMC),对其遗传方式及致病性进行了分析,认为sSMC(10)是该患者的致病原因。

Genetic diagnosis and etiological analysis were performed on a patient with hypoxic-ischemic encephalopathy at birth. MRI technology was used to examine the brain of the child. G-band karyotype analysis technology was used to analyze the karyotype of the child and her parents. Chromosomal microarray analysis(CMA) was used to analyze the entire genome of the child and her parents for chromosomal copy number variation(CNV) and to identify the small supernumerary marker chromosomes. The results of MRI supported the diagnosis of hypoxic-ischemic encephalopathy of the child and found the appearance of Dandy-Walker malformation. Karyotype analysis showed that the mother’s karyotype was 46, XX, t(10;13)(p11. 1;q11)[11]/46, XX[19]. The karyotype of the father was normal. The karyotype of the child was 47, XX, + mar. The CMA results showed that there was no CNVs above 200 kb in the parents. The CMA results of the child showed that the chromosome 10 was repeated in p15. 3 p11. 1, and the fragment size was 38. 39 Mb. In conclusion, this study found a rare small supernumerary marker chromosome(sSMC) on chromosome 10. Its genetic pattern and pathogenicity were analyzed. It is considered that sSMC(10) is the cause of the patient.