Two heterozygous mutations in the gene associated with Cockayne syndrome in a Chinese patient

Objective To confirm diagnosis and explore the genetic aetiology in a Chinese patient suspected to have Cockayne syndrome (CS). Methods The patient was clinically examined, and the patient and her biological parents underwent genetic analysis using whole exome sequencing (WES) and Sanger sequencing. The foetus of the patient’s mother underwent prenatal diagnostic Sanger sequencing using amniotic fluid obtained at 19 weeks’ gestation. Results Clinical examination of the patient showed developmental delay, progressive neurologic dysfunction and premature aging. Two compound, heterozygous ERCC excision repair 6, chromatin remodelling factor ( ERCC6 ) gene mutations were detected in the proband by WES and confirmed by Sanger sequencing, comprising a known paternal nonsense mutation (c.643G > T, p.E215X) and a novel maternal short insertion and deletion mutation (c.1614_c.1616delGACinsAAACGTCTT, p.K538_T539delinsKNVF). The patient was consequently diagnosed with CS type I. The foetus of the patient’s mother was found to carry only the maternally-derived c.1614_c.1616delGACinsAAACGTCTT variant. Conclusion This study emphasized the value of WES in clinical diagnosis, and enriched the known spectrum of ERCC6 gene mutations.