Analysis Of The Novel Factor X Gene Mutation Val (GTC) 384Ala (GCC) In One Family Resulting In Congenital Factor X Deficiency

Object:To detect the factor X gene mutation in one pedigree with the congenital factor X deficiency.Materials and Methods:PT,APTT and FX:C were texted for diagnosis of phenotype.FX antigen were measured with a sandwich enzyme-linked immunoadsorbent assay(ELISA)for classification.The eight exons,exon-intron boundaries and 5' untranslated sequences in factor X of the proband were amplified by PCR.The PCR products of all those above were purified and then sequenced directly.The DNA sequences of the other pedigree members were amplified in the mutation region of the proband and then sequenced.Results:Prolonged PT and APTT was found.Evaluation of the coagulation factors revealed that FX coagulation activity(FX:C)was 2.4%and FX antigen was 7.8%.The phenotype of the proband was diagnosed as FX deficiency(typeⅠ).28140 T—C homozygous mutation located in the exon 8 of factor X in the proband.Another variation was -343- -384 homozygous deletion of six nucleotides that located in promoter of factor X gene.By gene polymorphism,the change was not pathogenic gene but polymorphism.Tracing the other pedigree members found that the homozygous mutation in the proband was derived from her father and mather respectively.Her grandmather,father,mather were all heterozygotes of the mutation and her sister was normal.Conclusion:It was the first report that the 28140 T—C namely Val(GTC) 384Ala(GCC)homozygous mutation in FX gene resulting in the congenital factor X deficiency.