Coffin-Siris syndrome and epilepsy.

Coffin-Siris syndrome is a rare genetic disorder defined by the presence of particular facial traits, congenital malformations, intellectual disability, and speech impairment. Epilepsy in Coffin-Siris syndrome has only occasionally been reported, and its features are poorly defined. We provide a detailed description of the clinical and instrumental findings of three patients with Coffin-Siris syndrome and epilepsy. The clinical diagnosis in our patients was confirmed by molecular analysis, which identified the presence of de novo mutations of ARID1B and SMARCB1 genes, in two patients and one patient, respectively. All the patients presented with epilepsy, with a mean age of seizure onset of 5.5 years. Seizures were brief and had a focal onset with secondary generalization. Electroencephalographic recording documented a unilateral, and less commonly bilateral, paroxysmal activity in the temporal, parietal, and occipital regions. Clinical response to anticonvulsive therapy was satisfactory, with a low rate of seizure recurrence. Our case series contributes to delineate the phenotype of Coffin-Siris syndrome. We wish this report could pave the way for further studies that will better define the prevalence and clinical manifestations of epilepsy in this rare syndrome.