一个蚕豆病遗传家系G6PD基因突变及X染色体失活偏移检测

Detection of G6PD gene mutation and skewed X chromosome inactivation in a genetic family with favism

对一蚕豆病遗传家系的G6PD基因突变进行分析,检测突变后G6PD酶活变化,并对先证者家系进行X染色体失活(XCI)偏移模式检测,从而预测G6PD突变女性携带者患蚕豆病的风险。取家系成员的外周血样,并提取基因组DNA,用聚合酶链式反应(PCR)和DNA测序法进行序列分析,确定先证者突变位点和突变类型及家庭成员遗传情况,若先证者的母亲和姐姐为G6PD突变携带者,则对先证者母亲和姐姐进行X染色体偏移检测以及酶活检测分析,以评估携带者患蚕豆病的风险,同时对研究对象进行随访。结果患者X染色体上G6PD基因发生点突变c.1376G>T;酶活性检测结果显示该突变使G6PD酶活性下降大约25%,导致蚕豆病发生。该家系的两位女性携带者X染色体失活偏移<80%,未来发生蚕豆病的可能性低。

To analyze the mutation of the G6PD gene in a genetic family with favism,and detect the change of G6PD enzyme activity and the skewed X-chromosome inactivation(XCI)mode of the proband family,to predict the risk of favism in females carriers with G6PD mutation,peripheral blood samples of family members were collected and genomic DNA was extracted.PCR and DNA sequencing methods were used for sequence analysis to determine the mutation sites and mutation types of probands and the genetic status of family members.If the mother and sister were heterozygotes of G6PD mutation,skewed X-chromosome inactivation detection and enzyme activity analysis were performed for them to assess the risk of favism in the carriers,and the study subjects were followed up.As a result,the point mutation of G6PD gene on patient X chromosome c.1376G>T;the results of enzyme activity test showed that the mutation reduced the activity of G6PD by about 25%,leading to the occurrence of favism.The X chromosome inactivation deviation of the two female carriers in this family is less than 80%,so the possibility of favism in the future is low.