Insights Into Cockayne Syndrome Type B: What Underlies Its Pathogenesis?

Cockayne Syndrome (CS) is an autosomal recessive disorder arising from mutations in either of two disease-associated genes, ERCC6 or ERCC8. CS patients exhibit cutaneous photosensitivity, neuropathological abnormalities, severe growth retardation, a distinctive facial appearance with pronounced sunken eyes, musculoskeletal anomalies, sensory impairment, and dental decay. Approximately 70% of all CS cases carry ERCC6 mutations; therefore, this review will focus solely on Cockayne Syndrome complementation group B (CS-B). CS-B exhibits several hallmarks of aging, including genomic instability, epigenetic modifications, loss of proteostasis, and mitochondrial failure. CS-B is proposed to result from the accumulation of DNA damage and the resulting transcription impairment. However, the main pathophysiological mechanisms underlying the severe cellular impairments observed in CS-B remain unclear. Here, we review the current literature to elucidate ERCC6-related mechanisms, highlighting the key and emerging pathological mechanisms underlying CS-B, as well as their putative interactions. Considering the mechanisms that heavily rely on ERCC6, we propose that CS-B pathogenesis arises from a combination of DNA damage accumulation, transcriptional dysregulation, and mitochondrial dysfunction. Furthermore, we argue that these molecular features influence each other, rather than acting as isolated mechanisms. This suggests that the crosstalk between mechanisms is a key factor for CS-B pathogenesis. Although efforts have been made to unveil CS-B pathogenesis, research is still lacking, hindering progress in understanding this deadly disease. Future work will prove crucial to determine the main contributor to CS-B pathogenesis and identify new interactions between CS-B-affected mechanisms.