Linear hypermelanosis in narrow bands, a mosaic pattern manifestation of dyskeratosis congenita?

Our research investigates two cases involving the TINF2 gene variant (c.844C>T), demonstrating distinct phenotypes of classic dyskeratosis congenita (DC) and a novel linear hypermelanosis in narrow bands like mosaic DC. The first patient presented with classic DC features linked to a germline mutation, while the second exhibited extensive linear hypermelanosis in narrow bands like pigmentary lesions attributed to somatic mosaicism. These findings underscore the critical role of genetic analysis, particularly in affected tissues, for understanding mosaic dermatoses. It also expand the phenotypic spectrum of DC and shed light on the molecular mechanisms underlying mosaic congenital dyschromatosis.