2023 ACMG Annual Clinical Genetics Meeting Digital Edition: Poster Gallery-The recurrent 15q11.2 deletion: A single laboratory experience

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The recurrent 15q11.2 deletion is a common finding in clinical copy number analysis, often associated with intellectual disability, developmental delay, seizures, and autism spectrum disorder. However, it is usually inherited from an unaffected parent, and population studies suggest that its impact is relatively small. A study aimed to further understand the clinical features of 15q11.2 deletion by comparing them with patients with benign recurrent CNVs and assessing the rate of secondary genetic findings in 15q11.2 deletion patients. <br /><br />The study utilized internal lab testing databases and conducted retrospective chart reviews. The results showed that the rate of clinical findings such as developmental delay, autism, ADHD, seizures, and congenital heart defects did not significantly differ between the 15q11.2 deletion cohort and the benign recurrent CNV cohort. Additionally, there was no significant difference in the rate of secondary diagnostic cytogenetic findings between the two cohorts.<br /><br />Further molecular testing was more frequently ordered for the benign recurrent CNV cohort, but the testing depths did not vary between the two cohorts. The rate of diagnostic secondary molecular findings was the same for both cohorts. <br /><br />A small percentage (17%) of patients with the 15q11.2 deletion had secondary diagnostic findings, and most of these findings were associated with the clinical features typically attributed to 15q11.2 deletion.<br /><br />In conclusion, many of the clinical findings attributed to the recurrent 15q11.2 deletion may be due to ascertainment bias in the patient populations referred for analysis. Patients with these clinical findings and the deletion should consider additional diagnostic genetic testing, as some may have diagnostic molecular findings. Developmental delay was the only finding found to be enriched in the 15q11.2 deletion cohort, although the odds ratio was small. The rate of additional molecular testing and the presence of secondary findings were similar between the 15q11.2 deletion cohort and the benign recurrent CNV cohort.

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Presenting Author - John Herriges, PhD; Co-Author - Jennifer Roberts, MS; Co-Author - Elena A. Repnikova, PhD; Co-Author - Lei Zhang, PhD, FACMG;

Meta Tag

Delineation of Diseases

Clinical Cytogenetics

array CGH

Co-Author Lei Zhang, PhD, FACMG

Co-Author Elena A. Repnikova, PhD

Co-Author Jennifer Roberts, MS

Presenting Author John Herriges, PhD

Keywords

recurrent 15q11.2 deletion

intellectual disability

developmental delay

seizures

autism spectrum disorder

inherited

population studies

benign recurrent CNVs

secondary genetic findings

clinical features