Cockayne Syndrome due to a maternally-inherited whole gene deletion of ERCC8 and a paternally-inherited ERCC8 exon 4 deletion

• Cockayne Syndrome causes growth failure and neurologic regression.
• Our patient had deletions of exon 4 of ERCC8 on one chromosome and exons 1–12 on the other.
• LINE and other repeat elements may predispose the region to deletions, insertions and inversions.
• This patient had diabetes mellitus which is rarely reported with Cockayne Syndrome.

Cockayne Syndrome (CS) is an autosomal recessive disorder that causes neurological regression, growth failure and dysmorphic features. We describe a Chinese female child with CS caused by deletions of exon 4 of ERCC8 on one chromosome and exons 1–12 on the other chromosome. By using chromosomal microarray, multiplex ligation-dependant probe analysis and long range PCR, we showed that she inherited a 277 kb deletion affecting the whole ERCC8 gene from the mother and a complex rearrangement resulting in deletion of exon 4 together with a 1656 bp inversion of intron 4 from the father. A similar complex rearrangement has been reported in four unrelated Japanese CS patients. Analysis of the deletion involving exon 4 identified LINE and other repeat elements that may predispose the region to deletions, insertions and inversions. The patient also had insulin-dependent diabetes mellitus, a rare co-existing feature in patients with CS. More research will be needed to further understand the endocrine manifestations in CS patients.