CDKN1C and alopecia: p63 is known to be crucial for the development and differentiation of stratified epithelium.1, 2, 11, 12 Mice deficient for all isoforms of p63 lack stratified epidermis and mammary glands.2 Mice lacking TAp63 have fragile skin, develop blisters, wounds that never heal and alopecia.5 The epidermal phenotypes of TAp63−/− are due to the transcriptional regulation of p57Kip2 by TAp63 to maintain skin-derived precursors, a stem cell found to be critical for wound healing and hair regeneration,5, 41 in quiescence.