ABSTRACT
The naked (N) mutation arose spontaneously in a stock of mice at Latvia University in Riga. This mutation was named naked because homozygous (N/N) mice lack the appearance of a hair coat, while heterozygotes develop a first hair coat but lose it between 10 to 14 days of age. Heterozygotes resemble normal Littermates until the first hair coat has grown out. Weight differences between heterozygotes and littermate controls are of no prognostic or diagnostic value. The velvet coat (Ve) mutation is closely linked to N on Chromosome 15, which was used to identify the location of the mouse keratin genes. The naked mouse mutation was considered to resemble the dominantly inherited human disease known as hydrotic ectodermal dysplasia, but the amino acid changes in the hairs are different between the two species. Hereditary alopecia, present at birth, has been a form of ectodermal dysplasia reported in Miniature poodles, Lhasa Apsos, Whippets, and Cocker Spaniels.
