RH50 gene analysis in patient AC. The G residue at the 3′ acceptor splice-site of intron 6 is mutated to A in patient AC, thus resulting in the skipping of exon 7. Normal splicings of introns 6 and 7 are indicated by the broken lines. The approximate position of primers A₃ and A_4, used to amplify intron 6, is indicated. Intron and exon sequences are in lowercase and uppercase, respectively.