Cockayne syndrome (CS) is an autosomal recessive multisystem degenerative disorder caused by the mutations in two complementary genes, namely the excision repair cross-complementation group 6 (ERCC6) (80%) [144] and the excision repair cross-complementation group 8 (ERCC8) (20%) (Table 2) [145]. The gene discussed is ERCC6; the disease is Cockayne syndrome.