chromosomal gain syndrome triploid syndrome http://purl.bioontology.org/ontology/SNOMEDCT/66651005 http://purl.obolibrary.org/obo/NCIT_C85204 https://en.wikipedia.org/wiki/Triploid_syndrome https://www.wikidata.org/wiki/Q56137331 3n syndrome A chromosomal condition in which a fetus has three copies of every chromosome instead of two. If this occurs in only some cells, it is called mosaic triploidy and is less severe. Most embryos with triploidy miscarry early in development. chromosome triploidy syndrome triploidy syndrome 69,XXX