<i>Hoxc13</i> mutant mice lack external hair

The study on Hoxc13 mutant mice revealed that mutations in the Hoxc13 gene led to significant defects in hair, nail, and filiform papilla development, resulting in hairlessness due to brittle hair fracturing at the skin surface. Homozygous mutant mice exhibited malformed nails and broken filiform papillae, and most did not survive past two weeks. The research indicated that Hoxc13 was crucial for the development of hair follicles, nails, and filiform papillae, suggesting a novel function for this gene in structural protein synthesis. Additionally, Hoxc13 mutants showed skeletal changes, highlighting the gene's role in a developmental program affecting various structures. This study was the first to demonstrate significant effects of an Antennapedia-class homeobox gene on hair development, implying broader developmental roles for Hox genes.