SYNGAP1 and intellectual disability, autosomal dominant 5: Finally, we found a de novoheterozygous frameshift mutation (c.1230delC, p.Ser410ArgfsTer30) in the patient's SYNGAP1 gene, which provided a clear molecular diagnostic basis for the observed neurodevelopmental phenotype and was consistent with the characteristics of autosomal dominant intellectual disability type 5 (MRD5).