Genetic analysis for a haemophilia B family with multi nucleotides deletion mutation of F9 gene / 中华检验医学杂志

ABSTRACT

Objective To conduct genetic diagnosis and prenatal diagnosis for a haemophilia B family with multi-nucleotides deletion mutation of F9 gene.Methods This is a genetic analysis.Whole exon mutation of the F9 gene was analyzed by PCR and Sanger sequencing for seven patients with the family of hemophilia B who consulted doctors in Henan Province People′s Hospital in April 2013.Suspected mutation was verified among non-hemophilia B members of the family and 100 healthy controls to rule out genetic polymorphism of the F9 gene.The above-mentioned detection results of hemophilia B gene , the pathogenic mutation of F9 gene in the family was clarified , and prenatal diagnosis was conducted for the female carriers in the family.It is recommended that the fetal gene detection should be conducted in amniotic fluid in the mid-term pregnancy of the female carriers of hemophilia , and then they can be informed of the non-hemophilia B fetus by the results of the gene detection .Results PCR and sequencing analysis has identified a deletion mutation of F9 gene c.185_188delGAGA[p.Glu62Asnfs?41]in seven hemophilia B patients.This mutation induced F9 gene frame shift mutation which led to early termination of F9 gene translation because there was a termination codon TAA at the 41th codon after the mutation site.The same mutation was not found among the non-hemophilia B members of the family and the 100 healthy controls. There were eight female carriers and nine female non-carriers in the family.Upon prenatal diagnosis , the Y chromosome sex-determining gene ( SRY ) in amniotic fluid was positive and no deletion mutation was observed in the F9 gene c.185_188.Conclusion The pathogenic mutation of F9 gene in the family was identified , which was helpful for prenatal diagnosis in female carriers .