Npc1^spm

This spontaneous mutation is an A-to-C substitution in the third base pair of intron 19, which destroys the splice donor site, leading to the retention of 43 intronic bases before a cryptic splice site splices to exon 20. The 43 base pair insertion generates a frame shift resulting in 30 novel amino acids followed by a premature termination codon. There is no evidence of wild-type splicing in spm transcripts. (J:179744)