SMC1A codon 496 mutations affect the cellular response to genotoxic treatments

Cornelia de Lange syndrome is a pleiotropic developmental syndrome characterized by growth and cognitive impairment, facial dysmorphic features, limb anomalies, and other malformations. Mutations in core cohesin genes SMC1A and SMC3 , and the cohesin regulatory gene, NIPBL , have been identified in Cornelia de Lange syndrome probands. Patients with NIPBL mutations have more severe phenotypes when compared to those with mutations in SMC1A or SMC3 . To date, 26 distinct SMC1A mutations have been identified in patients with Cornelia de Lange syndrome. Here, we describe a 3‐year‐old girl with psychomotor and cognitive impairment, mild facial dysmorphic features but no limb anomaly, heterozygous for a c.1487G>A mutation in SMC1A which predicts p.Arg496His. We show that this mutation leads to an impairment of the cellular response to genotoxic treatments. © 2011 Wiley Periodicals, Inc.