J Korean Child Neurol Soc.  2018 Dec;26(4):272-275. 10.26815/jkcns.2018.26.4.272.

Early Diagnosis of KBG Syndrome Using Diagnostic Exome Sequencing

Affiliations
  • 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. SEHEEKIM@yuhs.ac
  • 3Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.

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.

Keyword

Developmental disabilities; ANKRD11 protein; KBG syndrome

MeSH Terms

Anticonvulsants
Atrial Septum
Developmental Disabilities
Early Diagnosis*
Electroencephalography
Exome*
Hearing Loss
Heart Septal Defects, Ventricular
Humans
Hypertelorism
Infant
Intellectual Disability
Language Development Disorders
Male
Neurodevelopmental Disorders
Neurologic Manifestations
Phenotype
Seizures
Anticonvulsants
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