KBG syndrome: Common and uncommon clinical features based on 31 new patients

Maria Gnazzo, Francesca R. Lepri, Maria Lisa Dentici, Rossella Capolino, Elisa Pisaneschi, Emanuele Agolini, Martina Rinelli, Viola Alesi, Paolo Versacci, Silvia Genovese, Claudia Cesario, Lorenzo Sinibaldi, Anwar Baban, Andrea Bartuli, Bruno Marino, Marco Cappa, Bruno Dallapiccola, Antonio Novelli, Maria Cristina Digilio

Research output: Contribution to journalArticlepeer-review


KBG syndrome (MIM #148050) is an autosomal dominant disorder characterized by developmental delay, intellectual disability, distinct craniofacial anomalies, macrodontia of permanent upper central incisors, skeletal abnormalities, and short stature. This study describes clinical features of 28 patients, confirmed by molecular testing of ANKRD11 gene, and three patients with 16q24 deletion encompassing ANKRD11 gene, diagnosed in a single center. Common clinical features are reported, together with uncommon findings, clinical expression in the first years of age, distinctive associations, and familial recurrences. Unusual manifestations emerging from present series include juvenile idiopathic arthritis, dysfunctional dysphonia, multiple dental agenesis, idiopathic precocious telarche, oral frenula, motor tics, and lipoma of corpus callosum, pilomatrixoma, and endothelial corneal polymorphic dystrophy. Facial clinical markers suggesting KBG syndrome before 6 years of age include ocular and mouth conformation, wide eyebrows, synophrys, long black eyelashes, long philtrum, thin upper lip. General clinical symptoms leading to early genetic evaluation include developmental delay, congenital malformations, hearing anomalies, and feeding difficulties. It is likely that atypical clinical presentation and overlapping features in patients with multiple variants are responsible for underdiagnosis in KBG syndrome. Improved knowledge of common and atypical features of this disorder improves clinical management.

Original languageEnglish
Pages (from-to)1073-1083
Number of pages11
JournalAmerican Journal of Medical Genetics, Part A
Issue number5
Publication statusPublished - May 1 2020


  • 16q24 deletion
  • ANKRD11 gene
  • KBG syndrome
  • macrodontia

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)


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