This mutation, discovered by its visible phenotype among the G1 progeny of an ENU mutagenized male mouse, comprises a T to A transversion at position 1123 of the gene (Genbank: NM_027983), in the sixth of its seven exons. This results in replacement of isoleucine by asparagine at amino acid position 353 of the keratin protein (I353N), in a region involved in protein-protein interactions. (J:145290)