Heterozygous deletion of SCN2A and SCN3A in a patient with autism spectrum disorder and Tourette syndrome: a case report

BACKGROUND: Mutations in voltage-gated sodium channel (SCN) genes are supposed to be of importance in the etiology of psychiatric and neurological diseases, in particular in the etiology of seizures. Previous studies report a potential susceptibility region at the chromosomal locus 2q including SCN1A, SCN2A and SCN3A genes for autism spectrum disorder (ASD). To date, there is no previous description of a patient with comorbid ASD and Tourette syndrome showing a deletion containing SCN2A and SCN3A. CASE PRESENTATION: We present the unique complex case of a 28-year-old male patient suffering from developmental retardation and exhibiting a range of behavioral traits since birth. He received the diagnoses of ASD (in early childhood) and of Tourette syndrome (in adulthood) according to ICD-10 and DSM-5 criteria. Investigations of underlying genetic factors yielded a heterozygous microdeletion of approximately 719 kb at 2q24.3 leading to a deletion encompassing the five genes SCN2A (exon 1 to intron 14–15), SCN3A, GRB14 (exon 1 to intron 2–3), COBLL1 and SCL38A11. CONCLUSIONS: We discuss the association of SCN2A, SCN3A, GRB14, COBLL1 and SCL38A11 deletions with ASD and Tourette syndrome and possible implications for treatment.