15q11.2 Deletion Syndrome: Expanding the Phenotype

Abstract

Background: Although multiple reports exist in the literature of patients with 15q11.2 deletion syndrome, the variability of the phenotype has made clinical delineation difficult. Neuro-developmental scores have not been previously reported. We present clinical findings in a group of 16 patients referred to our center for evaluation and management of neurodevelopmental difficulties. Methods: All patients were seen in our center between 2005 and 2016. They were seen by a clinical geneticist and their diagnosis of 15q11.2 deletion syndrome was confirmed by a microarray analysis. Bayley Scales of Infant Development was done and provided a mental developmental index and a motor developmental index. The data collected was then compared to previous reports in the literature of patients with 15q11.2 deletion syndrome. Results: The reviewed group consisted of 10 males and 6 female patients between the ages of 3 and 15 years. The most common clinical findings included developmental delay (94%), hypotonia (88%), ADHD (75%), anxiety (50%), feeding difficulties (44%), autism (31%), dolichocephaly (25%), 2-3 toe syndactyly (19%), seizure activity (19%), and congenital heart disease (13%). Additional findings included prominence of the metopic suture, epicanthal folds, micrognathia, ankle torsion, incontinence, and sleeping difficulties. Our developmental evaluation by the Bayley Scales of Infant Development indicated an average Mental Developmental Index of 75 (NL = >85) and Motor Developmental Index of 75 (NL = >85) in the patients less than 3 years old. Close to 43% of patients had an occipitofrontal circumference (OFC) greater than or equal to the 97th. Conclusion: The data provided here intends to expand the phenotype of the 15q11.2 deletion syndrome. Neurodevelopmental scores have not been previously reported in 15q11.2 del syndrome which were found to be in the mild developmental delay range.