Cockayne syndrome

Cockayne syndrome is a rare inherited disorder characterized by impaired growth, progressive neurological deterioration, photosensitivity, and features of premature aging. It is usually caused by defects in transcription-coupled nucleotide excision repair.

Transcription-coupled nucleotide excision repair: A DNA-repair pathway that removes lesions blocking transcription from active genes. Cockayne syndrome proteins help restart or repair transcription stalled by DNA damage.
Photosensitivity: An abnormal skin or systemic response to exposure to light, especially ultraviolet radiation. Light sensitivity is a characteristic feature of Cockayne syndrome.
Xeroderma pigmentosum: A genetic disorder of nucleotide excision repair characterized by extreme ultraviolet sensitivity and greatly increased skin-cancer risk. Unlike Cockayne syndrome, skin cancers are a prominent risk in classic xeroderma pigmentosum.
Genetic testing: Laboratory analysis of DNA to identify variants associated with a condition or inherited risk. Testing ERCC6 and ERCC8 can confirm many suspected cases and support family counseling.
ERCC6: A gene encoding the CSB protein, which helps cells respond to transcription-blocking DNA damage. Pathogenic ERCC6 variants cause most cases of Cockayne syndrome type B.
Microcephaly: A head size substantially smaller than expected for age and sex, often reflecting atypical brain growth. Progressive or congenital microcephaly can accompany the syndrome's impaired growth.
Trichothiodystrophy: A group of inherited disorders often marked by brittle sulfur-deficient hair, developmental impairment, and photosensitivity. It can resemble Cockayne syndrome, but brittle hair is a characteristic distinguishing feature.
Whole-exome sequencing: A method that sequences the protein-coding portions of genes across the genome. It can help identify causative variants when the clinical presentation is uncertain.
ERCC8: A gene encoding the CSA protein, which participates in transcription-coupled DNA repair. Pathogenic ERCC8 variants cause Cockayne syndrome type A.
Neurodegeneration: The progressive loss of structure or function in neurons and nervous-system networks. Neurological deterioration is a defining part of the syndrome's course.

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Rothmund–Thomson syndromeCompared with: Photosensitivity and poor growth overlap, but progressive neurological features are more characteristic of Cockayne syndrome.