ERCC3 is a crucial member of the NER pathway, deficiencies of which result in a heterogeneous group of disorders ranging from UV-sensitive syndrome to cancer-prone xeroderma pigmentosum, as well as the neurodevelopmental/progeroid conditions Trichothiodystrophy, Cockayne syndrome and Cerebro-oculo-facio-skeletal-syndrome [16]. Here, ERCC3 is linked to Cockayne syndrome.