Cockayne syndrome: infantile onset in two siblings and its clinical spectrum in India

Cockayne syndrome (CS) is a rare autosomal recessive disorder having myriad manifestations including features of growth failure, premature ageing, photosensitivity and progressive neurological degeneration. Often, a characteristic facial phenotype is also described. Mutations in the ERCC6 or ERCC8 genes, which impair DNA repair mechanisms, are responsible for CS. Mutations in the ERCC6 gene are reported commonly. Due to its rarity and overlap with other neurodegenerative disorders, Cockayne syndrome often presents significant diagnostic challenges, especially in early life. This case report discusses a unique case of 2 two siblings with CS, challenging the typical understanding due to the absence of photosensitivity. The index child presented with growth failure, developmental delay, including motor and speech impairment, with microcephaly and progeroid appearance. Genetic testing confirmed a mutation in the ERCC8 gene, consistent with Cockayne syndrome type A. This case is unique due to the absence of photosensitivity, which is conventionally considered a hallmark feature, highlighting the variability in the phenotypic expression of Cockayne syndrome. Despite established features, Cockayne syndrome remains underdiagnosed, hence under-reported, particularly in milder or atypical cases. The rarity and marked variability in clinical presentation often leads to delayed diagnosis, impacting timely management and genetic counselling. Given its complex presentation, clinicians must maintain a high level of suspicion in children with multisystem involvement who exhibit phenotypic features of Cockayne. This report reinforces the necessity of early recognition and intervention. Timely diagnosis is essential for appropriate management and genetic counselling, potentially altering the trajectory for affected families.