[Application of long distance-PCR to hemophilia A carrier detection and prenatal diagnosis].
OBJECTIVE
To establish an effective laboratory examination system for carrier detection and prenatal diagnosis of haemophilia A (HA).


METHODS
Twenty-five carriers of severe HA were directly detected by long-distance PCR (LD-PCR) in search of the factor FVIII (FVIII) gene inversion. Prenatal diagnosis was carried out using pregnant woman's venous blood sample, husband's venous blood sample and fetal navel venous sample at 20-24 weeks of gestation. The plasma coagulation factor VIII activity (FVIII:C) was detected by one-stage method. The concentration of von Willbrand factor (Vwf) was assayed by ELISA. Prenatal diagnosis was finally made by LD-PCR. The results of LD-PCR were proved by DNA sequencing.


RESULTS
Eight out of 25 cases were diagnosed as having FVIII geneinversion. Four of these 8 carriers underwent the LD-PCR for prenatal diagnosis, and 2 of them had to terminate pregnancy because their fetuses were diagnosed as having HA. The other two carriers were finally diagnosed to have normal fetuses by combined use of LD-PCR with plasma FVIII:C, vWF in pregnant woman's venous blood, husband's venous blood and fetal navel venous blood, and the one-year follow-up study demonstrated that the babies were normal and living well.


CONCLUSIONS
LD-PCR technique was adopted in this study to detect the factor VIII gene inversion; it could accurately and rapidly diagnose the severe cases of HA and could be used for the HA carriers in need of pregnant diagnosis.
Institute of Immunology, Medicine School of Shandong University, Jinan, Shandong, 250012 P.R. China. pfding2000@163.com
Pei-fang
PF
Ding
Qin-you
QY
Wang
Wen-sheng
WS
Sun
Xue-qin
XQ
Zhang
Bin
B
Teng
Fa-kui
FK
Shen
D005169:Factor VIII / Q000235:genetics; D005260:Female; D006467:Hemophilia A / Q000175:diagnosis* / Q000235:genetics*; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D015203:Reproducibility of Results
D005169:Factor VIII