Introduction

Cockayne syndrome (CS) is a rare progeroid disorder caused by biallelic pathogenic variants in ERCC6 or ERCC8, impairing transcription-coupled nucleotide excision repair (TC-NER) [1, 2]. Its clinical triad of postnatal growth failure, progressive neurodegeneration, and cutaneous photosensitivity is accompanied by broader multisystem involvement, including hearing loss, retinal dystrophy, dental anomalies, and hepatic dysfunction [1, 3].

Progressive spasticity and leukodystrophy in CS frequently produce fixed lower-limb contractures [4]. Severe rigid equinovarus deformity, driven by Achilles tendon contracture, is a debilitating yet poorly characterized complication causing intractable pain, loss of ambulation, and orthotic intolerance [4, 5]. The orthopedic literature offers little guidance on the surgical correction of these deformities in CS.

Surgical decision-making is complicated by the systemic fragility inherent to CS, including heightened anesthetic sensitivity, potential hepatotoxicity, and the syndrome’s progressive, fatal course [6]. We report a 10-year-old boy with CS type B and compound heterozygous ERCC6 mutations who underwent successful bilateral fractional elongation of the Achilles tendon (ETA) despite markedly elevated hepatic transaminases, aiming to describe a reproducible surgical technique, a perioperative framework for multisystem fragility, and the role of multidisciplinary care, including genetic counseling [1, 3, 6].