BackgroundIntellectual developmental disorder 7 (also namedDYRK1Asyndrome) is an autosomal dominant disease. The main clinical features ofDYRK1Asyndrome include intellectual disability, microcephaly, and developmental delay. This study aimed to identify pathogenic variants in a Chinese girl with developmental delay, impaired social interaction, and autistic behavior.Case presentationThe case was a 6-year-old girl. Clinical symptoms of the patient mainly included developmental delay, seizures, autistic behavior and impaired social interaction. The patient presented with microcephaly, bushy eyebrows, a short lingual frenum, binocular esotropia, bilateral valgus and external rotation, and walked with an abnormal gait. Using whole-exome sequencing, we identified a 9,424 bpde novoheterozygous deletion (containing coding exons 10, 11, and 12, and partial sequences of non-coding exon 12) inDYRK1A, which is responsible forDYRK1Asyndrome. TheDYRK1Avariant is classified as pathogenic according to the criteria of the American College of Medical Genetics and Genomics.ConclusionsThe findings of this study augment the data regarding the pathogenic variants ofDYRK1Aand provide important information for molecular diagnosis.