Rhino-9J (hr(rh9J)): a new allele at the hairless locus.

A spontaneous mutation arose in the MRL/MpJ-Fas(lpr)/Fas(lpr) colony in which mice lost hair after completion of the first hair cycle. Hair loss was progressive from head to tail. As these mice aged, they developed wrinkled skin and long curved nails. Histologically, affected skin developed comedones (pilary cysts), deep dermal cysts, and dermal foreign body granulomas associated with rupture of the follicles. The alopecic epidermis was acanthotic. The mutation was autosomal recessive. Crosses with RHJ/Le +/hr(rhJ) (rhino-J) mutant mice yielded affected offspring with the same phenotype, verifying the presence of a new allele of rhino, a mutation at the hairless (hr) locus on mouse chromosome 14.