Despite the natural progression of Cockayne's syndrome, affected patients also present with variable neurological and gastrointestinal damage (gastroesophageal reflux, recurrent vomiting, swallowing disorders, etc.) with varying repercussions on their growth. Acute intercurrent events such as seizures, constipation, infections can also interact with their metabolism, food intake and influence their growth. The nutritional deficit potentially involved in this growth retardation can be responsible for many manifestations such as anemia, bone fractures, fatigue, coagulation disorders responsible in total for the reduction in quality and life expectancy.

Faced with growth retardation in patients with Cockayne syndrome, medical management is difficult to establish. Is this delay part of the natural course of the pathology?

Inclusion criteria:

• Minor patient
• Cockayne syndrome with molecular confirmation, treated between 01/01/1985 and 01/03/2020
• Collection of at least one growth data (height, weight, head circumference) for a given age
• Clinic compatible with type 1 or 2 Cockayne syndrome
• Holder of parental authority not opposing, after information, the reuse of their child's medical data for the purposes of this scientific research.

Exclusion criteria:

• Refusal to participate in the study.
• Lack of molecular confirmation of Cockayne syndrome
• Lack of growth data for a given age.
• Clinic not compatible with type 1 or 2 Cockayne syndrome. Exclusion of type 3 Cockayne syndromes, trichothiodystrophy and xeroderma-pigmentosum.

Minor patient with cockayne syndrome with molecular confirmation, treated between 01/01/1985 and 01/03/2020