One of the first steps of the TC‐NER cascade is the sequential recruitment of Cockayne Syndrome (CS) CSB and CSA proteins on the DNA template, in transcribed genomic regions of active genes where RNA Polymerase II (RNAPII) stalls at bulky DNA lesions (Vermeulen & Fousteri, 2013). The gene discussed is ERCC6; the disease is Cowden syndrome 1.