Novel Mutation of SYNGAP1 Associated with Autosomal Dominant Mental Retardation 5 in a Chinese Patient.
Autosomal dominant de novo mutations in SYNGAP1 are a cause of intellectual disability (ID) and autism spectrum disorder (ASD), including autosomal dominant mental retardation 5 (MRD5). By performing exome sequencing, we discovered a novel heterozygous variant in SYNGAP1 (c.509 + 1G > A) in a 4-year-old ethnic Chinese boy with ID and ASD but without seizures or malformation. The c.509 + 1G > A mutation in the SYNGAP1 gene was present in a patient with MRD5.