P 1155. Focal Epilepsy Difficult to Treat in Hermann–Pallister’s Syndrome (KBG Syndrome)

Background: In connection with the power of next-generation sequencing (NGS) a lot of more rare syndromes can be diagnosed nowadays. In our case, the outer suspicious signs of the patient were initially hidden by a focal epilepsy resistant to therapy.

Methods: We would like to present a meanwhile 11-year-old girl who initially presented at our hospital with an epilepsy difficult to treat dominated by focal onset nonaware seizures and auras. Under a combination therapy of valproate and oxcarbazepine, the girl became almost seizure free. Initially, leading symptoms were a behavioral disorder with aggressive and autoaggressive behavior, stereotypes, and mild mental retardation. The patient also showed facial dysmorphia with macrodontia, prominent dysplastic ears, hypertelorism, synophris, low hairline, and short fingers. She developed a pituitary dwarfism and a central hypothyroidism.

Results: After the metabolic investigations including lysosomal enzymes and magnetic resonance imaging of the brain showed no abnormalities, we initiated genetic counseling and diagnostic including NGS where a heterozygous mutation of the ANKRD11 gene was found, which has been described as a cause of the rare Hermann–Pallister’s syndrome. This syndrome has been described by the following features: dysmorphia, short stature, intellectual disability, costovertebral bone anomalies, behavioral disorder, conductive hearing loss, brain malformation, and epilepsy. The epilepsy in the syndrome is seldom resistant to therapy. In rare cases, successful treatment with growth hormone has been reported.

Conclusion: Especially in the present time of modern diagnostic options such as NGS, rare syndromes should be published to sharpen our clinical view. The KBG syndrome is definitely underdiagnosed.

In case of a diagnosis, a substantiated genetic counseling can be performed to inform the families about the repetition risk of the disease.