P 366. 7q11.23 Microduplication Syndrome: Neurophysiological and Neuroradiological Insights into a Rare Chromosomal Disorder

Background: The phenotypical consequence of the heterozygous chromosome 7q11.23 interstitial microdeletion is the Williams–Beuren’s syndrome, a very well-known genetic multisystemic disorder. Much less is known about the reverse condition, the heterozygous interstitial microduplication of 7q11.23 region. The first molecular cytogenetic description was published in 2005 and only after several years, the reported patients were numerous enough to attempt a description of a common phenotype

Aims: Characterization of neurophysiological and neuroradiological features of 7q11.23 duplication syndrome.

Objectives: Diagnosis of 7q11.23 duplication syndrome on the basis of clinical, neurophysiological, and neuro-radiological features.

Methods: By using a broad multidisciplinary approach, we investigated 12 patients with this rare genetic anomaly. Ten of them harbored the duplication of the classical WBS region and two a slightly larger duplication. Upon a detailed description of the clinical and psychological features, we used electroencephalography and magnetic resonance imaging to explore neurophysiological function and brain structures.

Results: We analyzed the clinical, psychological, neuroradiological, and neurophysiological features of 12 yet unpublished individuals affected by this rare genetic anomaly, focusing specifically on the last two aspects. Several structural abnormalities of the central nervous system were detected, such as ventriculomegaly, hypotrophic cerebellum, hypotrophic corpus callosum, and hypoplastic temporal lobes. Although only 1 of 12 individuals suffered from seizures during childhood, 3 others had abnormal electroencephalography findings prominent in the anterior brain regions, without any visible seizures to date.

Conclusion: Taken together, we enlarged the yet in the literature underrepresented cohort of patients affected by 7q11.23 microduplication syndrome and shed further light on neuroradiological and neurophysiological aspects of this rare genetic syndrome.