Introduction of alternative splice sites in cases 26 and 30. (A) Case 26, the T>A replacement in the intron results in a frame shift that makes a new splice acceptor 11 bp upstream (5′) of the authentic splice acceptor. (B) Case 30, a 4-bp deletion, including splice donor sites, resulted in use of 2 cryptic splice donor sites 208 bp and 108 bp downstream (3′) of the authentic splice donor site. WT indicates wild-type; MT, mutants.