Further delineation of the KBG syndrome phenotype caused by ANKRD11 aberrations

Charlotte W Ockeloen, Marjolein H Willemsen, Sonja de Munnik, Bregje W M van Bon, Nicole de Leeuw, Aad Verrips, Sarina G Kant, Elizabeth A Jones, Han G Brunner, Rosa L E van Loon, Eric E J Smeets, Mieke M van Haelst, Gijs van Haaften, Ann Nordgren, Helena Malmgren, Giedre Grigelioniene, Sascha Vermeer, Pedro Louro, Lina Ramos, Thomas J J MaalCeleste C van Heumen, Helger G Yntema, Carine E L Carels, Tjitske Kleefstra

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Loss-of-function variants in ANKRD11 were identified as the cause of KBG syndrome, an autosomal dominant syndrome with specific dental, neurobehavioural, craniofacial and skeletal anomalies. We present the largest cohort of KBG syndrome cases confirmed by ANKRD11 variants reported so far, consisting of 20 patients from 13 families. Sixteen patients were molecularly diagnosed by Sanger sequencing of ANKRD11, one familial case and three sporadic patients were diagnosed through whole-exome sequencing and one patient was identified through genomewide array analysis. All patients were evaluated by a clinical geneticist. Detailed orofacial phenotyping, including orthodontic evaluation, intra-oral photographs and orthopantomograms, was performed in 10 patients and revealed besides the hallmark feature of macrodontia of central upper incisors, several additional dental anomalies as oligodontia, talon cusps and macrodontia of other teeth. Three-dimensional (3D) stereophotogrammetry was performed in 14 patients and 3D analysis of patients compared with controls showed consistent facial dysmorphisms comprising a bulbous nasal tip, upturned nose with a broad base and a round or triangular face. Many patients exhibited neurobehavioural problems, such as autism spectrum disorder or hyperactivity. One-third of patients presented with (conductive) hearing loss. Congenital heart defects, velopharyngeal insufficiency and hip anomalies were less frequent. On the basis of our observations, we recommend cardiac assessment in children and regular hearing tests in all individuals with a molecular diagnosis of KBG syndrome. As ANKRD11 is a relatively common gene in which sequence variants have been identified in individuals with neurodevelopmental disorders, it seems an important contributor to the aetiology of both sporadic and familial cases.

Original languageEnglish
Pages (from-to)1176-85
Number of pages10
JournalEuropean journal of human genetics
Issue number9
Publication statusPublished - Sept 2015


  • Abnormalities, Multiple/diagnosis
  • Adolescent
  • Adult
  • Autism Spectrum Disorder/complications
  • Bone Diseases, Developmental/complications
  • Child
  • Child, Preschool
  • Chromosomes, Human, Pair 16
  • DNA Mutational Analysis
  • Exome
  • Facies
  • Female
  • Gene Deletion
  • Gene Expression
  • Genotype
  • Humans
  • Intellectual Disability/complications
  • Male
  • Middle Aged
  • Phenotype
  • Repressor Proteins/genetics
  • Tooth Abnormalities/complications

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