Cockayne syndrome. An update

Cockayne's syndrome is a rare heterogeneous autosomal recessive disorder with poor genotype-phenotype correlation. The basic underlying abnormality in CS is defective transcription-coupled repair of DNA whereas the global genome repair pathway of nucleotide-excision repair is normal. Clinically the spectrum of CS spans from classical type (CS type 1, CKN1, CSA), a more severe form with symptoms present at birth (CS type 2, CSB, also known as cerebro-oculo-facial syndrome and Pena-Shokeir type II syndrome), a milder form (CS type 3), and xeroderma pigmentosum-Cockayne syndrome (XP-CS). However, CS type 1 and CS type 2 are the major phenotypes. The cardinal features of CS are growth failure, premature aging, and pigmentary retinal degeneration along with a number of nonspecific clinical findings. The definite diagnosis requires assay of DNA repair in skin fibroblasts or lymphoblasts. Prenatal diagnosis is also possible at 16-18 weeks of gestation. There is progressive downhill course with premature death before adulthood. Besides genetic counselling a multidisciplinary approach is required.