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