Observational Study to Assess Natural History in Cockayne Syndrome Patients

Inclusion Criteria: * Pediatric patients with a documented diagnosis of CS, as suggested by clinical features and possible confirmation by genetic consultation and analysis * Age of participation: * At least 12 months of age at the time of signing Informed Consent/Assent * Female patient's age will not be greater than 10 years of age at the time of signing Informed Consent/Assent * Male patient's age will not be greater than 11 years of age at the time of signing Informed Consent/Assent Exclusion Criteria: * Severe contractures or physical deformities that in the opinion of the investigator would prevent accurate measurement of height, length and ulna length * Patients that have taken growth hormone or growth hormone related medications within 12 months prior to the date of Informed Consent/Assent * Known history of inborn error of hyperprolinemia (Type I or Type II) * Clinical features present at the time of initial screening that are associated with the terminal phases of the natural progression of CS suggesting safe travel and completion of the study and its assessments to be unlikely as judged by the Investigator, including any of the following: * Continuous or intermittent dependence on supplemental oxygen at home during the prior six months * Two or more hospitalizations for pneumonia during the prior 12 months; * A documented net weight loss of at least 10%, which has not been recovered and which includes a significant net weight loss (beyond the estimated error of the measurement) over the most recent 6 months, despite intensive nutritional support including the use of gastrostomy tube feedings * Presence of scoliosis with a Cobb's angle of 30º or greater