14例染色体不平衡易位的遗传学分析

Genetic analysis of 14 cases with unbalanced chromosomal translocation

目的分析14例染色体不平衡易位胎儿的遗传变异方式,为其家庭再次妊娠的复发风险评估提供依据。方法应用染色体核型分析结合单核苷酸多态微阵列芯片(single nucleotide polymorphism array,SNP-Array)对胎儿及其父母进行全基因组DNA扫描分析。结果 14例SNP芯片检测存在染色体不平衡易位的胎儿包括多种常见的临床综合征,核型分析结果显示11例核型异常,3例正常。加做3例核型正常胎儿的父母芯片,结果均显示正常,根据芯片结果提示重新分析,确诊3例胎儿实际为亚显微的染色体不平衡易位者,父母为隐性易位携带者。最终确诊遗传来源11例,母源性9例,父源性2例,新发突变3例。结论确定不平衡易位胎儿的遗传变异方式,对其家庭的复发风险评估提供依据,尤其是亚显微的染色体不平衡改变,对隐性易位携带者的复发风险评估有重要价值。

Objective To analyze the genetic variation of 14 fetus with unbalanced chromosomal translocation,so as to provide evidence for the recurrence risk assessment of the family.Methods Using karyotype analysis and single nucleotide polymorphism array to analyze the genome variants of fetal and their parents.Results 14 cases of fetus with unbalanced translocation of chromosomes were detected by SNP chip including a variety of common clinical syndrome.Karyotype analysis showed 11 cases with chromosome abnormality and 3 cases with normal karyotype; plus 3 cases of normal karyotype fetal parents of the chip,the results were normal,according to chip results prompted re-analysis,it is suggested that 3 cases of normal karyotype were diagnosed as a submicroscopic unbalanced translocation of chromosomes,and the parents were implicit translocation carriers.The final diagnosis of genetic was 11 cases,maternal in 9 cases; paternal in 2 cases,new variants in 3 cases.Conclusion It has important value to determine the unbalance of genetic variation mode of translocation of the fetus,and can provide basis for the evaluation of the risk of recurrence of the family,especially the submicroscopic chromosomal imbalance change and the concealed translocation carrier recurrence risk assessment.