Trichothiodystrophy 3, Photosensitive, also known as trichothiodystrophy, complementation group a, is related to cockayne syndrome and trichothiodystrophy. An important gene associated with Trichothiodystrophy 3, Photosensitive is GTF2H5 (General Transcription Factor IIH Subunit 5), and among its related pathways/superpathways are Processing of Capped Intron-Containing Pre-mRNA and Homology Directed Repair. Affiliated tissues include skin and testis, and related phenotypes are intellectual disability and failure to thrive