Early Diagnosis of KBG Syndrome Using Diagnostic Exome Sequencing |
Jun Ho Hong1, Se Hee Kim2, Seung Tae Lee3, Jong Rak Choi3, Hoon Chul Kang2, Joon Soo Lee2, Heung Dong Kim2 |
1Department of Pediatrics, Severance Children’s Hospital, Yonsei University College of Medicine, Seoul, Korea 2Division of Pediatric Neurology, Department of Pediatrics, Epilepsy Research Institute, Severance Children’s Hospital, Yonsei University College of Medicine, Seoul, Korea 3Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea |
Correspondence:
Se Hee Kim, Tel: +82-2-2328-2050, Fax: +82-2-393-9118, Email: SEHEEKIM@yuhs.ac |
Received: 24 September 2018 • Revised: 10 October 2018 • Accepted: 11 October 2018 |
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Abstract |
KBG syndrome is a rare neurodevelopmental disorder characterized by intellectual disability, skeletal anomalies, short stature, craniofacial dysmorphism, and macrodontia. ANKRD11 gene mutation and 16q24.3 microdeletion have been reported to cause KBG syndrome. Here, we report two patients with ANKRD11 mutations who initially presented with neurologic symptoms such as developmental delay and seizures. Patient 1 was a 23-month-old boy who presented with a global developmental delay. Language delay was the most dominant feature. He had hypertelorism, hearing impairment, and behavior problems characterized as hyperactivity. A c.1903_1907delAAACA (p.Lys635GInfsTer26) mutation in ANKRD11 was identified with diagnostic exome sequencing. Patient 2 was a 14-month-old boy with developmental delay and seizure. He also had atrial septum defect, and ventricular septal defect. Generalized tonic seizures began at the age of 8 months. Electroencephalography showed generalized sharp and slow wave pattern. Seizures did not respond to antiepileptic drugs. A loss of function mutation c.5350_5351delTC (p.ser1784HisfsTer12) in ANKRD11 was identified with diagnostic exome sequencing. In both cases, characteristic features of KBG syndrome such as short stature or macrodontia, were absent, and they visited the hospital due to neurological symptoms. These findings suggest that more patients with mild phenotypes of KBG syndrome are being recognized with advances in diagnostic exome sequencing genetic technologies. |
Key Words:
Developmental disabilities, ANKRD11 protein, KBG syndrome |
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