Exon6-intron6 and intron6-exon7 junctions in the RH gene. (A) Exon6/exon7 boundary was found at positions 939/940, as we had previously reported.2 (B) Setting exon6/exon7 boundary at positions 940/941, as suggested by Huang,1 results in abnormal 5′ (GT → TA) and 3′ (AG → GG) splice sites. Invariant +1 and −2 residues at the 5′ donor and 3′ acceptor splice sites, respectively, are underlined.