title: Phenotypic variability in fetuses with down syndrome: a case-control pathological evaluation.
abstract: OBJECTIVE
  Evaluation of morphological and morphometric characteristics of fetuses with Down syndrome based on a detailed postmortem examination and comparison of these fetuses with a control group of fetuses with normal karyotype to improve the prenatal knowledge of Down syndrome characteristics.
  
  
  METHODS
  A case-control study was undertaken in a tertiary referral hospital. The Down syndrome fetuses (50) were compared with chromosomally normal fetuses (47) matched for gestational age. Biometric and morphological parameters were compared.
  
  
  RESULTS
  The biometry of fetuses with Down syndrome differs from control fetuses only in the occipitofrontal diameter and in the nasal bone length. There were craniofacial anomalies in 96% of fetuses with Down syndrome and in 51% of fetuses with normal karyotype. With the exception of small ears, all craniofacial features analyzed were significantly different between Down syndrome fetuses and control fetuses. All extremity features of fetuses with Down syndrome were significantly different from fetuses without Down syndrome. There were 31 fetuses with Down syndrome (62%) with 55 internal anomalies. Nineteen fetuses (38.8%) showed 27 cardiac anomalies. Six fetuses had more than one anomaly. There were 18 fetuses (36%) with 28 noncardiac anomalies.
  
  
  CONCLUSIONS
  The importance of studying the morphological characteristics of fetuses with Down syndrome is the contribution to a better knowledge of fetal characteristics and probably to optimize prenatal diagnosis.
authors.affiliation: Center of Prenatal Diagnosis, Department of Gynecology and Obstetrics, Centro Hospitalar S. João, Medical Faculty of Porto, Porto, Portugal. carlaramalho@med.up.pt
authors.forename: C
authors.initials: C
authors.lastname: Ramalho
authors.forename: O
authors.initials: O
authors.lastname: Brandão
authors.forename: A
authors.initials: A
authors.lastname: Matias
authors.forename: N
authors.initials: N
authors.lastname: Montenegro
mesh_terms: D037881:Aborted Fetus / Q000473:pathology*; D000649:Amniocentesis; D001699:Biometry; D016022:Case-Control Studies; D015193:Chorionic Villi Sampling; D004314:Down Syndrome / Q000000981:diagnostic imaging / Q000473:pathology*; D005315:Fetal Diseases / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008423:Maternal Age; D009295:Nasal Bone / Q000000981:diagnostic imaging / Q000473:pathology; D048208:Nuchal Translucency Measurement; D010641:Phenotype; D012886:Skull / Q000000981:diagnostic imaging / Q000473:pathology