Ring chromosome 20 with normal number of chromosomes (Q101739)

Ring chromosome 20 syndrome is a chromosomal anomaly 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. Initial psychomotor development is usually unaffected and pre- and postnatal growth are normal. There is no recognizable dysmorphism although strabismus, micrognathia, down-slanting palpebral fissures, and ear abnormalities have been reported in some affected individuals.