Carrier detection and prenatal diagnosis of hemophilia Alpha.

OBJECTIVE

To establish an effective laboratory examination system for carrier detection and prenatal diagnosis of haemophilia Alpha(HA) with a variety of molecular biological methods which are simple,rapid and easy to use.

METHODS

Detection of inversion involving intron 22 in the FVIII gene was completed by long distance polymerase chain reaction (PCR) and linkage analysis was performed by using several genetic polymorphisms including an intragenic Bcl I RFLP, 2 STRs and an extragenic St14 VNTR.

RESULTS

Intron 22 inversion was observed in 10 out of the 21 (47.6%) pedigrees examined. Prenatal diagnosis was completed in 3 pedigrees. A further combination of the four intragenic and extragenic polymorphic loci gave an informative rate of 94.7%.

CONCLUSIONS

Female relatives in HA families with inversion can be detected with direct diagnostic procedure. The application of long distance PCR makes the detection much more simple and rapid. For families without inversions,it is easier and more cost-effective to undertake linkage analysis of genetic polymorphism based on PCR.