(Top) Nucleotide sequence of a part of exon XI for normal and case no. 1. The 4-bp deletion is boxed. Codon 464 becomes a termination signal because of a reading frame-shift. (Bottom) Nucleotide sequence of a part of exon XII for normal and case no. 2. Mutated nucleotide A is indicated in a box, and a normal Gly562 residue is substituted with an abnormal Arg sequence.