Supplementary Material for: Body focused repetitive behaviors in patients with FOXP1 syndrome: an international cross-sectional survey-based study

Introduction: FOXP1 syndrome is a rare neurodevelopmental disorder due to forkhead box protein 1 (FOXP1) gene mutations and is associated with intellectual disability, dysmorphic features, and autism spectrum disorder. We aimed to assess body focused repetitive behavior (BFRB) prevalence in this patient population using a cross-sectional survey-based study. Methods: A validated survey assessing for BFRBs was administered to parents attending the International FOXP1 Foundation conference 6/21/2023 and was sent to a FOXP1 syndrome listserv. Results: Excoriation disorder, onychophagia, onychotillomania, and trichotillomania were reported by 58.6%, 38.6%, 29.7%, and 10.0% of subjects, with 63.4%, 59.3%, 54.5%, and 14.3% having moderate to severe disease, respectively. Overall, 28.6%, 30.0%, and 10.0% had one, two, and three BFRBs, respectively. Conclusion: Prevalence of BFRBs is high amongst FOXP1 syndrome patients, affecting quality of life for patients and their families, and causing significant sequelae.