RT-PCR amplification products from factor VIII-VBP1 chimeric mRNA transcripts in 5 severe hemophilia A patients.

Nested primers in factor VIII exon 1 combined with primers in VBP1 exon 2 produced a 500-bp band. The control lane RT-PCR contained normal lymphocyte RNA. Sequence analysis (not shown) revealed factor VIII exon 1 and 2 facultative exons followed by VBP1 exon 2.