A syndrome characterized by multiple system abnormalities including dwarfism; photosensitivity disorders; premature aging; and hearing loss. It is caused by mutations of a number of autosomal recessive genes encoding proteins that involve transcriptional-coupled dna repair processes. Cockayne syndrome is classified by the severity and age of onset. Type I (classical; csa) is early childhood onset in the second year of life; type II (congenital; csb) is early onset at birth with severe symptoms; type iii (xeroderma pigmentosum; XP) is late childhood onset with mild symptoms. [MeSH]