Inherited defects in NER are manifested in different diseases including xeroderma pigmentosum (XP), Cockayne syndrome (CS), UV sensitive syndrome (UVsS) and the photosensitive form of trichothiodystrophy (TTD).
This deficiency is further confirmed by the inability of TTD/XPD cells to recruit, specifically for CPDs, NER factors that arrive in a TFIIH-dependent manner later in the NER pathway.
The consequences of a defect in one of the NER proteins are apparent from three rare recessive syndromes: xeroderma pigmentosum (XP), Cockayne syndrome (CS) and the photosensitive form of the brittle hair disorder trichothiodystrophy (TTD).