Besides, the brain CT, MRI, ECG examination, clinical investigations including intelligence testing, chromosomal karyotype analysis, serum amino acid determination, blood ammonia, and succinyl acetone level testing extracted in peripheral blood at 2.5 years old were conducted for the proband with exon3_exon4del variant in DYRK1A. Results of intelligence testing indicated intellectual disability (ID) in terms of social activity, language, fine motor skills, and sport. Here, DYRK1A is linked to Intellectual disability.