title: Triploidy: Variation of Phenotype.
abstract: OBJECTIVE
  Triploidy (69, XXX; 69, XXY; 69, XYY) accounts for 1% of conceptions, but the affected fetus often does not survive past the first trimester. Fetal development in triploidy is rare. A consecutive series was used to describe the fetal and placental phenotypes and compare them with previous publications.
  
  
  METHODS
  Fifty-four triploid fetuses were identified in the Active Malformations Surveillance Program between 1972 and 2012 at Brigham and Women's Hospital in Boston. The phenotype was described from prenatal imaging and autopsy findings.
  
  
  RESULTS
  The diagnosis was confirmed by chromosome analysis in 53 of the 54 fetuses. Twenty-seven (50%) of the affected fetuses were identified during pregnancy. The abnormalities identified by prenatal ultrasound included renal malformations, heart defects, hydrocephalus, holoprosencephaly, and myelomeningocele. At autopsy, syndactyly, usually between fingers 3 and 4, was identified in 37 (69%) of the fetuses. Thirteen (24%) of the infants had the histologic features of a partial hydatidiform mole in the placenta.
  
  
  CONCLUSIONS
  The presence of major malformations and growth restriction during pregnancy makes triploidy a potential diagnosis. There are no obligate clinical features in triploidy. Syndactyly, especially 3-4 syndactyly of the hands, is a distinctive feature. Cystic changes in the placenta can be seen by ultrasound during pregnancy. There was no difference in the phenotype between triploid infants associated with partial moles and those with nonmolar placentas.
authors.affiliation: From the Medical Genetics Unit, MassGeneral Hospital for Children, Harvard Medical School, Boston, MA Department of Pediatric Newborn Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA htoufaily@mgh.harvard.edu.
authors.forename: M Hassan
authors.initials: MH
authors.lastname: Toufaily
authors.affiliation: Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston.
authors.forename: Drucilla J
authors.initials: DJ
authors.lastname: Roberts
authors.affiliation: From the Medical Genetics Unit, MassGeneral Hospital for Children, Harvard Medical School, Boston, MA Department of Pediatric Newborn Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
authors.forename: Marie-Noel
authors.initials: MN
authors.lastname: Westgate
authors.affiliation: From the Medical Genetics Unit, MassGeneral Hospital for Children, Harvard Medical School, Boston, MA Department of Pediatric Newborn Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
authors.forename: Lewis B
authors.initials: LB
authors.lastname: Holmes
mesh_terms: D000328:Adult; D005260:Female; D005865:Gestational Age; D006801:Humans; D006828:Hydatidiform Mole / Q000000981:diagnostic imaging*; D007621:Karyotyping; D010641:Phenotype; D010920:Placenta / Q000000981:diagnostic imaging; D011247:Pregnancy; D011296:Prenatal Diagnosis; D057885:Triploidy; D014463:Ultrasonography; D014594:Uterine Neoplasms / Q000000981:diagnostic imaging*
keywords: Congenital malformations; Non-molar placenta; Partial hydatidiform mole; Phenotype; Syndactyly; Triploidy