一例15号额外标记染色体的遗传学分析

Genetic analysis of a supernumerary derivative chromosome 15

目的探讨15q11-13拷贝数增加与智力障碍、语言发育落后及孤独症等表型的关系并探讨细胞遗传学技术与分子遗传学技术相结合进行诊断的可行性及优越性。方法应用常规G显带染色体核型分析技术、多重连接依赖性探针扩增技术及微阵列比较基因组杂交技术对1例额外标记染色体进行遗传学分析。结果患者核型为47，XY，＋mar。多重连接依赖性探针扩增技术结果显示额外标记染色体来源于15号染色体，并存在母源性拷贝数复制增加。微阵列比较基因组杂交显示基因组拷贝数变异区域为15q11-13，大小9．8Mb，基因位点：20477397-30298155。结论15q11-13区域拷贝数复制增加与患者语言发育落后、智力低下及孤独症等l临床表现密切相关。传统的细胞遗传学分析技术与微阵列比较基因组杂交技术相结合，有利于检测结果的相互补充与验证，从而获得更为精确的遗传学数据，为进一步研究染色体畸变、基因组重排与临床表型的关系奠定了基础。

Objective To detect and analyze a supernumerary derivative chromosome 15 with combined cytogenetic and molecular techniques, and to discuss the correlation between genomic copy number variations （CNVs） and clinical phenotypes. Methods G-banded chromosome analysis and multiplex ligation-dependent probe amplification （MLPA） were carried out. The whole genome of the patient was also analyzed with array-comparative genome hybridization（array-CGH）. Results G-banding analysis indicated that the patient has a karyotype of 47,XY, q-mar, with the supernumerary chromsome derived from 15ql 1- 13 region spanning 9.8 Mb from locus 20477397 to 30298155. Conclusion CNVs of 15q11-13 are associated with mental retardation, language development delay and autistic disorder. Conventional cytogenetic analysis with array-CGH may provide a platform for accurate detection of chromosomal aberrations, which can faciliate the study of genome rearrangement underlying various diseases.