Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) With Language Impairment Accompanied by Developmental Disability Caused by Forkhead Box Protein 1 (FOXP1) Exon Deletion: A Case Report

Forkhead box protein 1 (FOXP1) (OMIM: 605515) is located at chromosomal region 3p14.1, which codes for a transcriptional repressor protein. FOXP1 syndrome (FOXP1S) (OMIM #613670) is caused by FOXP1 gene deletions and mutations (nonsense, missense, and in-frame deletions). It is identified by the presence of intellectual disability with language impairment, with or without autistic features. This paper describes the case of a seven-year-old girl mainly presenting with autism spectrum disorder, language impairment, and intellectual disability. In addition, she also exhibited signs of attention deficit hyperactivity disorder. Whole-exome sequencing showed that she had a mutation in the FOXP1 gene; the variant revealed was FOXP1: NM_001244813 with a deleted segment (1152-1164) of exon 11. Subsequently, she was diagnosed with FOXP1 syndrome. In order to manage behavioral disturbance, risperidone was given, and she showed marked improvement. In this article, we report the characteristic features of attention deficits hyperactivity in addition to previously reported autism spectrum disorder with language impairment accompanied by intellectual disability caused by FOXP1 exon deletion. This study aims to provide a systematic, comprehensive presentation of a patient with a FOXP1 mutation to contribute to the existing literature on this subject.