Introduction: Deletion or duplication of the recurrent ~600 kb BP4-BP5 region on 16p11.2 (chr 16: 29,649,996-30,199,855 in hg19) has been associated with a wide range of neurodevelopmental outcomes with a prevalence of approximately 0.6% (ranging from 0.3 to 1% across studies) of all patients ascertained for Autism Spectrum Disorder (ASD), and 0.4% (ranging from 0.3 to 0.7%) in large series of patients with intellectual disability (ID) or birth defects. These rates are significantly higher than the estimated background population prevalence of .04-.05%. In addition to the increased need for psychiatric and behavioral intervention, the inherent neurological disruptions associated with these gene defects may lead to an increased need for neurosurgical interventions. The purpose of this study is to investigate and describe the surgeries of which these patients are at higher risk (as well the associated risk factors) in hopes to better inform practitioners.

Methods: To clarify the phenotype of 16p11.2 deletion and duplication, we examined psychiatric/developmental presentation and gathered extensive histories of predominantly clinically referred individuals, with a particular emphasis on broader autism phenotype characteristics in individuals with de novo and inherited recurrent ~600 kb chromosome 16p11.2 deletions or duplications. Individuals with these gene defects, and familial controls, were evaluated for symptom presentation, clinical diagnosis, and medical/surgical history gathered across 3 clinical sites.

Results: Children with 16p11.2 deletions or duplications have more neurosurgeries than the general population. We will present the profile of these surgeries stratified by deletion vs. duplication and controlled for age, sex, and IQ.

Conclusions: Patients with genetic anomalies have been shown to have a greater need for neurosurgery. Similarly, those with psychiatric disorders have been shown to have an increased need for specific surgeries. This is consistent with our findings for clinically referred patients with 16p11.2 gene deletions or duplications (who also have an increased risk of psychiatric disorders).

Patient Care: By informing practitioners of the increased need for surgery in this population, they can better counsel patients and families with a 16p11.2 deletion or duplication.

Learning Objectives: By the conclusion of this session, participants should be able to counsel families with 16p11.2 gene deletions or duplications on the importance of early neurosurgical involvement and possible intervention.

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