KBG Syndrome

KBG syndrome is characterized by macrodontia of the upper central incisors, a distinct craniofacial appearance, skeletal abnormalities and neurological involvement that includes developmental delay, intellectual disabilities and seizures. KBG syndrome is considered a subphenotype of 16q24.3 microdeletion syndrome, which includes the craniofacial appearance, seizures and developmental delay. However, individuals with a 16q24.3 microdeletion may have a more complex phenotype because autism and structural and neuronal migrational brain abnormalities have also been reported. Most cases of KBG syndrome have been de novo but familial cases have been documented. GeneDx conducts bi-directional sequence analysis of 11 coding exons and the flanking exon/intron boundaries of the ANKRD11 gene. If no mutation is identified by sequencing, whole genome array CGH is available to detect deletions involving ANKRD11 in 16q24.3.

Tests Available

Forms and Documents

Test Details

  • Confirmation of a clinical diagnosis
  • Carrier testing for individuals with a known familial ANKRD11 mutation
  • Prenatal diagnosis in at-risk pregnancies


3 weeks
2-5 mL Blood - Lavender Top Tube
Buccal Swabs

*Reporting times are typical, but could be extended in situations outside GeneDx's reasonable control.


For price inquiries please email zebras@genedx.com

**The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.


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  2. S. Sacharow et al., “Familial 16q24.3 Microdeletion Involving ANKRD11 Causes a KBG-Like Syndrome”. Am J of Med Genet Part A Vol. 158A: 547-552 (2012).
  3. M.H. Willemsen et al., “Identification of ANKRD11 and ZNF778 as candidate genes for autism and variable cognitive impairment in the novel 16q24.3 microdeletion syndrome”. Eur J of Human Genet Vol 18: 429-435. (2010)
  4. M. Isrie et al., “Haploinsufficiency of ANKRD11 causes mild cognitive impairment, short stature and minor dysmorphisms”. Eur J of Hum Genet Vol 20: 131-133 (2012).
  5. E.L. Youngs et al., “ANKRD11 gene deletion in a 17-year-old male”. Clinical Dysmorphology Vol 20: 170- 171. (2011)
  6. F. Brancati et al., “KBG syndrome in a cohort of Italian patients”. Am J Med Genet Part A Vol. 131A: 144- 149 (2004).
  7. A. Sirmaci et al., “Mutations in ANKRD11 Cause KBG Syndrome, Characterized by Intellectual Disability, Skeletal Malformations, and Macrodontia”. Am J Hum Genet Vol 89: 289-294 (2011).
  8. A. Zhang et al., “Identification of a novel family of ankyrin repeats containing cofactors for p160 nuclear receptor coactivators”. J Biol. Chem Vol. 279: 33799-33805 (2004).
  9. A. Zhang et al., “Characterization of transcriptional regulatory domains of ankyrin repeat cofactor-1”. Biochemical and Biophysical Research Communications Vol.358: 1034–1040 (2007).