Prenatal diagnosis of a trisomy 7/maternal uniparental heterodisomy 7 mosaic fetus

Karl Y. Bilimoria, Jeffrey M. Rothenberg*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Chromosomal segregation anomalies often result in trisomy of a single chromosome, which can lead to a disastrous phenotype in the fetus. However, this trisomy is often "rescued" via loss of one of the triploid chromosomes. Depending on which chromosome is eliminated in the rescue, a condition known as uniparental disomy may arise where both copies of a particular chromosome pair originate from the same parent. Here we describe the case of a 32-year-old woman who was prenatally diagnosed with trisomy 7 mosaicism via amniocentesis. Forty-one percent of the colonies analyzed displayed trisomy 7 (two maternal chromosomes and one paternal chromosome); whereas, 59% of the colonies demonstrated a normal, disomic karyotype. Further analysis revealed that the "normal" cell lineage displayed maternal uniparental heterodisomy. Chorionic villus tissue was homogenously trisomic, and cord blood cells were uniformly disomic. This is the first case of trisomy 7/uniparental disomy 7 mosaic fetus reported in the literature. It is important to note that not all such cases will result in lethality or a fetus with major anatomic, developmental, or cognitive abnormalities. In addition, the benefit of pre- and post-screening test counseling and support is discussed in reference to fetuses with chromosomal abnormalities in general and our case in particular. 2003 Wiley-Liss, Inc.

Original languageEnglish (US)
Pages (from-to)60-63
Number of pages4
JournalAmerican Journal of Medical Genetics
Volume118 A
Issue number1
StatePublished - Apr 1 2003


  • Amniocentesis
  • Mosaicism
  • Prenatal diagnosis
  • Triple marker screen
  • Trisomy 7
  • Uniparental disomy

ASJC Scopus subject areas

  • Genetics(clinical)
  • Genetics


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