1例18号染色体部分单体和部分三体嵌合核型患儿的细胞遗传学分析

王晓菲; 梁俊漪; 彭雅彬; 鲍布和; 张晨晰; 刘晓婷; 张文玲; 汪伟伟; 张立文; 王成彬

doi:10.3969/j.issn.2095-5227.2019.09.004

1例18号染色体部分单体和部分三体嵌合核型患儿的细胞遗传学分析

Cytogenetics analysis in a patient with partial monosomy 18p and partial trisomy 18q

摘要

摘要:
目的对1例发育迟缓、智力低下伴头部发育异常的患儿进行染色体核型分析并验证异常染色体来源。
方法 5岁女性患儿于2014年因发育迟缓、智力低下来解放军总医院第一医学中心就诊。运用染色体核型分析技术、单核苷酸多态性微阵列技术检测异常核型，并设计特异性探针采用荧光原位杂交实验验证患儿的染色体核型。
结果染色体核型分析结果为46, XX, del(18)(p11)34/46, XX, add(18)(p11)16，短臂缺失的18号染色体与增加片段的18号染色体核型比例为34/16；SNP Array检测结果为arr 18p11.32p11.22(136, 227-10, 213, 704)x1，显示该患儿18号染色体18p11.32-p11.22区段存在10 Mb片段的缺失，检测结果同时显示患者18p11.22-18qter有低比例的三体性嵌合；FISH检测结果为46, XX, .ishdel(18)(p11.2)(18pter-, 18qter+, WCP18+)166/psudic(18)(p11.2)(18pter-, 18qter++, WCP18+)34，验证了染色体核型和SNP Array结果提示的异常染色体来源。
结论患儿染色体核型为46, XX, del(18)(p11.2)34/46, XX, psudic(18)(p11.2)16，为新生突变；患儿智力低下及发育异常可能是由2种异常核型共同作用所致，但并未表现出18p缺失综合征、18部分三体综合征临床症状中的严重缺陷，这可能是由嵌合性核型导致的；染色体核型分析结合SNP Array、FISH等技术能够更准确地鉴定异常染色体。

Abstract:
Objective To analyze the chromosome karyotype of a girl with delayed development, mental retardation and abnormal brain development and verify the source of the abnormalities.
Methods A 5-year-old girl with delayed development, mental retardation and abnormal brain development admitted to the first medical center of Chinese PLA General Hospital in 2014. The patient's chromosome was analyzed and verified using karyotype analysis, single nucleotide polymorphisms array (SNP Array) and fluorescence in situ hybridization (FISH) analysis.
Results G-binding analysis showed a chromosome karyotype of 46, XX, del(18)(p11)34/46, XX, add(18)(p11)16. The SNP Array analysis detected a 10Mb chromosome fragment deletion of 18p11.32-p11.22, or 18p11.32p11.22(136, 227-10, 213, 704) x1, and a chromosome fragment of 18p11.22-18qter with a low repeated mosaic. FISH analysis further confirmed the karyotype was 46, XX, . ishdel (18) (p11.2) (18pter-, 18qter+, WCP18+)166/psudic(18)(p11.2)(18pter-, 18qter++, WCP18+)34.
Conclusion The chromosome karyotype of the patient is 46, XX, del (18) (p11.2)34/46, XX, psudic (18) (p11.2)16, which is a new mutation. The mental retardation and developmental abnormalities in this patient may be caused by the effect of two kinds of abnormal chromosome karyotypes. However, the patient has not shown serious clinical symptoms of 18p minus syndrome and 18-trisomy syndrome because of the chimeric condition. Chromosome karyotype analysis combined with SNP Array and FISH analysis can identify abnormal chromosomes more accurately.

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