The Gene Detection And Carriers Analysis Of Three Haemophilia B Families

ObjectiveHemophilia B is a serious hazard to human health of genetic diseases. Through the detection and analysis of three hemophilia B families'FIX gene mutation, establish a simple, accurate and rapid genetic diagnosis method of haemophilia B; to reveal the molecular mechanisms of the disease; determine the carrier to prevent the birth of children and reduce the incidence of hemophilia B; simultaneously have some practical significance to clear the injury-disease relationship in the forensic identification.MethodsAfter collection of three families with hemophilia clinical data and blood samples, genomic DNA were extracted. All of the 8 exons and their flanks of coagulation factor IX gene were amplified by polymerase chain reaction (PCR) and direct sequencing. The linkage relationships were analyzed by extragenic sIX polymorphic and highly heterozygous short tandem repeat loci of factor IX (DXS 102, DXS1192,DXS1211,DXS1227,DXS8013 and DXS8094).ResultsSequence analysis showed that a 6409 Gâ†'A mutation was found in the patients from family 1, which caused the 12nd amino acid Gly to Arg. Memberâ…¢3 from family lwas as the normal female for the 6409th base "G". A 6364 Câ†'T mutation was detected in the patients from family 2, which caused the-4th amino acid Arg to Trp. Memberâ…¡9 from family 2 was as normal female for the 6364th base "C". However, Memberâ…¢6 carried the corresponding heterozygous mutation. The patients from family 3 had a 30383 Gâ†'C mutation, which caused the135th amino acid Val to Leu. Memberâ…¡2 from family 3 was as normal female for the 30383rd base "C". Not any other mutation was found in all patients. The linkage results supported memberâ…¢3 from family 1 carried the normal X chromosome by DXS8094 and DXS 1211. Memberâ…¡9 from family 2 obtained the normal X chromosome by DXS 1211 and DXS 102, whileâ…¢6 obtained the disease-causing X chromosome.ConclusionReplacement mutations are the main mechanisms of the three hemophilia B families; we found a case of carrier; mutation analysis combined with linkage analysis is an effective way to detect carriers.