Trichothiodystrophy, also known as ttd, is related to trichothiodystrophy 1, photosensitive and trichothiodystrophy 4, nonphotosensitive. An important gene associated with Trichothiodystrophy is ERCC2 (ERCC Excision Repair 2, TFIIH Core Complex Helicase Subunit), and among its related pathways/superpathways are Infectious disease and Processing of Capped Intron-Containing Pre-mRNA. Affiliated tissues include skin and eye, and related phenotypes are spasticity and abnormal pyramidal sign