1例孕11周拟诊Patau综合征产前诊断分析及规范产前诊断思考

Prenatal diagnosis analysis of one fetus(eleven weeks of pregnancy) which is to be diagnosed patau syndrome and the think of standardize prenatal diagnosis

目的通过查找1例孕11+3周阴道彩超发现胎儿畸形病因,明确患胎的超声表型与遗传学之间的关系,告知该患胎母亲再次妊娠的方式选择、遗传学分析及产前诊断注意事项。方法经遗传学分析,采用常规绒毛染色体核型、QF-PCR及单核苷酸多态微阵列芯片技术对患胎及其父母进行遗传学检查,准确了解其携带的染色体不平衡易位的位置和大小。在此基础上建议患胎母亲再次妊娠的方式选择、遗传学分析及产前诊断注意事项。结果单核苷酸多态微阵列芯片提示患胎存在7号染色体和13号染色体的不平衡易位。染色体结构异常的发生来源于携带平衡易位的父亲。经单核苷酸多态微阵列芯片检测,患胎存在7q33q36.3区段检出22.31Mb缺失;染色体13q31.1q34区段检出32.72Mb重复,属于易位型Patau综合征。患胎超声影像中存在全前脑畸形、独眼畸形较为特异性的13三体综合征表型,符合临床判断。经遗传咨询告知患者再次妊娠方式选择方式及优缺点及再次妊娠相关产前诊断注意事项。结论阴道彩超检查可以提高孕早期胎儿结构异常检出率;重视遗传学分析,利用结构异常的患胎作为先证者进行相关遗传学检测利于明确病因,单核苷酸多态微阵列芯片分析技术的结合有助于鉴别特殊标本染色体核型异常,为实现精准医疗进行产前诊断遗传咨询提供了依据。

Objective To find out the pathogeny by transvaginal ultrasound of a fetal anomaly 11 ＋ 3 week of pregnancy, identify the relationship between the clinical phenotype and genetics of the fetal anomaly, and to provide genetic counseling for the patient about the mode selection of second pregnancy, genetic analysis and the matters needing attention in prenatal diagnosis.Methods The phenotypic and chromosomal analysis of the affected fetus and its parents were performed by using karyotype analysis, QF-PCR and chromosome microarrays technology, accurately understand the location and size of the chromosomal imbalance translocation it carries. Provide genetic counseling for the patient about the mode selection of second pregnancy, genetic analysis and the matters needing attention in prenatal diagnosis.Results The results of single nucleotide polymorphic microarray chip indicated that the imbalance translocation exists on the 7th and 13th chromosome of the affected fetus. The source of the structure abnormity was from its father carrying a balanced translocation. 22.31Mb deletion in 7q33q36.3 region and 32.72Mb repetition in 13q31.1q34 region was also found. The fetal phenotype and genotype were similar to the Patau syndrome. The specific phenotype of trisomy 13 syndrome including total forebrain malformation and monocular malformation were found in fetal ultrasound images. After genetic counseling, the patients were informed of the choice of re- pregnancy mode, the advantages and disadvantages, and the precautions for prenatal diagnosis related to re-pregnancy.Concluslons The ultrasound imaging combined with genetic analysis can improve the detection rate of fetal structural abnormality in early pregnancy. We should pay attention to genetic analysis, utilize the structure abnormity fetus to carry out related genetic detection does good to clear the cause of disease. The combination of single nucleotide polymorphic microarray technique can help to identify chromosomal karyotype abnormalities in special specimens. It provides the basis for genetic counseling ofprenatal diagnosis in accurate medical treatment.