Cockayne syndrome

Cockayne syndrome (CS) is a rare recessive disorder characterized by progressive multisystem abnormalities such as postnatal growth deficiency, progressive pigmentary retinopathy, sensorineural hearing loss, dental caries and neurological degeneration. CS has thus been classified as a segmental premature-aging syndrome. Two complementation groups (CSA and CSB) have been identified so far in CS cases. CSA caused by mutation in the gene encoding the group 8 excision-repair cross-complementing protein (ERCC8) is early childhood onset in the second year of life. CSB caused by mutation in the ERCC6 gene is late childhood onset with mild symptoms. ERCC8 encodes a Walker domain (WD)-repeat protein involved in the transcription-coupled repair system of the actively transcribed DNA. ERCC6 protein is at the interface of transcription and DNA repair and is involved in transcription-coupled and global genome-DNA repair, as well as in general transcription.