A TP63 Mutation Causes Prominent Alopecia with Mild Ectodermal Dysplasia

A spectrum of TP63-related disorders with eight affected individuals in five unrelated families

TP63-related disdorders broadly involve varying combinations of ectodermal dysplasia (sparse hair, hypohydrosis, tooth abnormalities, nail dysplasia), cleft lip/palate, acromelic malformation, split-hand/foot malformation/syndactyly, ankyloblepharon filiforme adnatum, lacrimal duct obstruction, hypopigmentation, and hypoplastic breasts and/or nipples. TP63-related disorders are associated with heterozygous pathogenic variants in TP63 and include seven overlapping phenotypes; Ankyloblepharon-ectodermal defects-cleft lip/palate syndrome (AEC), Ectrodactyly-ectodermal dysplasia-cleft lip/palate syndrome 3 (EEC3), Limb-mammary syndrome (LMS), Acro-dermo-ungual-lacrimal-tooth syndrome (ADULT), Rapp-Hodgkin syndrome (RHS), Split-hand/foot malformation 4 (SHFM4), and Orofacial cleft 8. We report on five unrelated families with 8 affected individuals in which the probands presented with varying combinations of ectodermal dysplasia, cleft lip/palate, split-hand/foot malformation, lacrimal duct obstruction, and ankyloblepharon filiforme adnatum. The clinical diagnosis involved AEC syndrome (2 patients), EEC3 syndrome (2 patients), and a yet hitherto unclassified TP63-related disorder. Sanger sequence analysis of the TP63 gene was performed revealing five different variants among which four were novel and three were de novo. The identificated TP63 variants co-segregated with the other affected individuals in the families. The abnormalities of ectoderm derived structures including hair, nails, sweat glands, and teeth should alert the physician to the possibility of TP63-related disorders particularly in the presence of orofacial clefting.

The Role of microRNAs in Organismal and Skin Aging

The aging process starts directly after birth and lasts for the entire lifespan; it manifests itself with a decline in an organism’s ability to adapt and is linked to the development of age-related diseases that eventually lead to premature death. This review aims to explore how microRNAs (miRNAs) are involved in skin functioning and aging. Recent evidence has suggested that miRNAs regulate all aspects of cutaneous biogenesis, functionality, and aging. It has been noted that some miRNAs were down-regulated in long-lived individuals, such as let-7, miR-17, and miR-34 (known as longevity-related miRNAs). They are conserved in humans and presumably promote lifespan prolongation; conversely, they are up-regulated in age-related diseases, like cancers. The analysis of the age-associated cutaneous miRNAs revealed the increased expression of miR-130, miR-138, and miR-181a/b in keratinocytes during replicative senescence. These miRNAs affected cell proliferation pathways via targeting the p63 and Sirtuin 1 mRNAs. Notably, miR-181a was also implicated in skin immunosenescence, represented by the Langerhans cells. Dermal fibroblasts also expressed increased the levels of the biomarkers of aging that affect telomere maintenance and all phases of the cellular life cycle, such as let-7, miR-23a-3p, 34a-5p, miR-125a, miR-181a-5p, and miR-221/222-3p. Among them, the miR-34 family, stimulated by ultraviolet B irradiation, deteriorates collagen in the extracellular matrix due to the activation of the matrix metalloproteinases and thereby potentiates wrinkle formation. In addition to the pro-aging effects of miRNAs, the plausible antiaging activity of miR-146a that antagonized the UVA-induced inhibition of proliferation and suppressed aging-related genes (e.g., p21WAF-1, p16, and p53) through targeting Smad4 has also been noticed. Nevertheless, the role of miRNAs in skin aging is still not fully elucidated and needs to be further discovered and explained.