Orphanet: Trisomy 18p

Search for a rare disease

* (*) mandatory field

Other search option(s)

Suggest an update

(*) Required fields.


Only comments seeking to improve the quality and accuracy of information on the Orphanet website are accepted. For all other comments, please send your remarks via contact us. Only comments written in English can be processed.

Orphanet doesn't provide personalised answers. To get in touch with the Orphanet team, please contact

Information provided in your contribution (including your email address) will be stocked in .CSV files that will be sent as an email to Orphanet's teams. These emails might be conserved in the teams' mailboxes, in our backoffice servers but will not be registered in our databases (for more information see our section General Data Protection Regulation and data privacy (GDPR) and Confidentiality).

Captcha image

Trisomy 18p

Disease definition

A rare partial trisomy of the short arm of chromosome 18 manifesting with a highly variable clinical phenotype which may include variable developmental delay and intellectual disability, epilepsy, and non-specific dysmorphic features, among others.


Classification level: Disorder
  • Synonym(s):
    • Duplication 18p
    • Duplication of the short arm of chromosome 18
    • Trisomy of the short arm of chromosome 18
  • Prevalence: <1 / 1 000 000
  • Inheritance: -
  • Age of onset: Infancy, Childhood, Adolescent, Adult
  • ICD-10: Q92.2
  • ICD-11: LD41.H1
  • OMIM: -
  • UMLS: C2931811
  • MeSH: C538307
  • GARD: 5323
  • MedDRA: -

Detailed information


ERN : produced/endorsed by ERN(s)
FSMR : produced/endorsed by FSMR(s)
The documents contained in this web site are presented for information purposes only. The material is in no way intended to replace professional medical care by a qualified specialist and should not be used as a basis for diagnosis or treatment.