A Case of GRIN1 Mutation Presenting with Autistic Features

GRIN1 mutations are characterized by neurodevelopmental disorder accompanied by hyperkinetic movements, autistic features and epilepsy. The disease is inherited in an autosomal dominant manner, but de novo mutations can also ocur. A three-year-old male patient, who admitted to our outpatient clinic with the complaint of inability to speak, had been followed up in child psychiatry department with the diagnosis of autism spectrum disorder since he was two years old. In the physical examination of the patient, hyperkinetic movements were observed and deep tendon reflexes of the lower and upper extremities were increased. Since these findings do not typically accompany autism spectrum disorder, metabolic tests, cranial magnetic resonance imaging, karyotype and microarray analysis were performed. These diagnostic methods show no abnormality. c.2796T>G heterozygous mutation in the GRIN1 gene was detected in the whole exome sequencing of the patient. Findings of hyperkinetic movements and hyperreflexia in a patient with autistic features may suggest GRIN1 mutations in the differential diagnosis.