Ring chromosome 20 syndrome

What is Ring chromosome 20 syndrome?

Ring chromosome 20 syndrome is marked by a characteristic seizure phenotype. Depending on the amount of chromosomal loss and associated mosaicism, ring(20) can be associated with macrocephaly, mild to moderate intellectual deficit, or behavioural problems. In rare cases, brain, kidney or heart malformations may be present.

Other condition names

  • Ring 20
  • Ring chromosome 20

Inheritance type



  • Worldwide: <1 in 1,000 000

Age of Onset

  • Adolescent
  • Adult
  • Childhood
  • Infancy
Orphadata: Free access data from Orphanet. © INSERM 1999. Available on "https://www.orphadata.com". Data version 1.3.16 / 4.1.7.