• Journal of the Korean Child Neurology Society
• /
• v.26 no.4
• /
• pp.272-275
• /
• 2018

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.

• Journal of Interdisciplinary Genomics
• /
• v.5 no.2
• /
• pp.13-17
• /
• 2023

KBG syndrome (KBGS) is a multisystem disorder characterized by short stature, distinctive facial features including macrodontia of upper central permanent incisors, and developmental/cognitive delay. It is caused by variants or deletion of Ankyrin Repeat Domain 11 (ANKRD11) located in chromosome 16q24.3. Since its initial report in 1975, KBG syndrome has been recognized as an exceedingly rare disorder. However, recent advancements in genetic diagnostic techniques have led to an increase in both the diagnosis rate and the number of reported cases, contributing to a rapid increase in its global prevalence. We review the clinical aspects of KBGS, including previously reported and newly reported cases, as well as the related genetic patterns discovered so far.

• Journal of Genetic Medicine
• /
• v.16 no.1
• /
• pp.39-42
• /
• 2019

KBG syndrome is an autosomal dominant syndrome presenting with macrodontia, distinctive facial features, skeletal anomalies, and neurological problems caused by mutations in the ankyrin repeat domain 11 (ANKRD11) gene. The diagnosis of KBG is difficult in very young infants as the characteristic macrodontia and typical facial features are not obvious. The youngest patient diagnosed to date was almost one year of age. We here describe a 2-month-old Korean boy with distinctive craniofacial features but without any evidence of macrodontia due to his very early age. He also had a congenital megacolon without ganglion cells in the rectum. A de novo deletion of exons 5-9 of the ANKRD11 gene was identified in this patient by exome sequencing and real-time genomic polymerase chain reaction. As ANKRD11 is involved in the development of myenteric plexus, a bowel movement disorder including a congenital megacolon is not surprising in a patient with KBG syndrome and has possibly been overlooked in past cases.