A 795 base-pair intragenic deletion resulted in the removal of the final 24 base-pairs of exon 6 and the first 771 base-pairs of intron 6. As a result of the mutation, 99 base-pairs of intron 6 are included in the mRNA and a cryptic splice donor within intron 6 is used to splice the mRNA to exon 7. The included intron 6 sequence encoded 13 novel amino acids before a premature termination codon was encountered, resulting in the loss of the final 78 amino acids of the protein. Immunoblot analysis of brain extracts failed to detect any protein. (J:142436)