ERCC2 and xeroderma pigmentosum: Nevertheless, patients with specific mutations of the genes coding for XPB or XPD, two proteins of the TFIIH complex, which has several roles in NER and beyond [11], or XPG, may develop a combination of Xeroderma Pigmentosum and Cockayne Syndrome (XP/CS), that associates the severe photosensitivity and the high skin cancer incidence to the neurologic and somatic manifestations of CS patients, worsening even more the prognosis of the patients [12].