Definite pathogenesis gene; Uses in the carrier picking out with the prenatal diagnosis; And may forecast the inhibitor the production.
(one) direct gene diagnosis: Uses the molecular biology method (the PCR, DGGE, SSCP, DNA sequence and so on) the immediate determinant pathogenesis gene flaw. FVIII 22 contain the sub-inversion analysis to be possible to take heavy HA the screening experiment, is also uses in the clinical diagnosis only at present the direct gene examination method. FVIII 22 contain the sub-inversion and other genes is accompanied by the inhibitor occurrence abnormal suddenly, therefore is helpful to the forecast inhibitor production.
(two) indirect gene diagnosis: (RFLP) takes the special molecular heredity designated object using the pathogenesis gene’s inside and outside restrictive fragment length polymorphism, chain-like relational determination hemophilia gene’s through the pedigree member’s between heredity situation, carries on the DNA polymorphism analysis the genetics diagnosis (methods and so on RFLP, VNTR, STR), may cause the diagnosis rate to reach 99%. RFLP analysis limitation: Must have proband’s specimen; The mother is this polymorphism position spot heterozygote, unites many RFLP only then to be possible to diagnose.
(three) prenatal diagnosis: May pregnant for 9-12 weeks to the high-risk embryo to pass the chorion biopsy; Pregnants for 12-16 weeks to carry on raises the water puncture, recently may also when the embryo implants through the early embryo (8 cells) gains embryo DNA, through the DNA genotype and the heredity phenotype definite embryo sex, as well as further judges whether for hemophilia or carrier. Pregnants for 18-20 weeks to be possible to take the umbilical vein blood under the fetoscope, determines FVIII:C and FVIII:Ag. The above method has miscarriage’s danger (approximately 0.5%-1%), must carries on under gynecologist’s instruction and the coordination. (FACS) determines in the parent substance venous blood using the class type cell technique the embryo specificity monoclonal antibody by the definite embryo sex, has provided the early time, not creates the natural prenatal diagnosis the method.