Angora Mouse Mutation: Altered Hair Cycle, Follicular Dystrophy, Phenotypic Maintenance of Skin Grafts, and Changes in Keratin Expression

The study focused on the angora mouse mutation, which was caused by a deletion in the fibroblast growth factor 5 (Fgf5) gene, leading to excessively long truncal hair due to a prolonged anagen phase of the hair cycle. Homozygous angora mice exhibited abnormal hair shaft structures and follicular dystrophy, with hair twisting within follicles causing secondary hyperplasia. These abnormalities were detectable from birth and persisted throughout life. The phenotype was maintained in skin grafts onto immunodeficient mice, indicating that the mutation's effects were not influenced by systemic factors. The angora mutation served as a valuable model for studying hair cycle regulation and keratin expression changes.