Cockayne syndrome – a primary defect in DNA repair, transcription, both or neither?

Cockayne syndrome is a rare autosomal recessive disease characterized by a complex clinical phenotype. Most Cockayne syndrome cells are hypersensitive to killing by ultraviolet radiation. This observation has prompted a wealth of studies on the DNA repair capacity of Cockayne syndrome cells in vitro . Many studies support the notion that such cells are defective in a DNA repair mode(s) that is transcription‐dependent. However, it remains to be established that this is a primary molecular defect in Cockayne syndrome cells and that it explains the complex clinical phenotype associated with the disease. An alternative hypothesis is that Cockayne syndrome cells have a defect in transcription affecting the expression of certain genes, which is compatible with embryogenesis but not with normal post‐natal development. Defective transcription may impair the normal processing of DNA damage during transcription‐dependent repair. ‘“Curiouser and curiouser” cried Alice.’ (Lewis Carroll, Alice's Adventures in Wonderland ).