Mosaic Trisomy 12: Prenatal Diagnosis at Amniocentesis and Molecular Genetic Analysis on Fetal Tissues

Paola Bonasoni, Gabriele Tonni, Giuseppina Comitini, Veronica Barbieri, Monia Rinaldini, Maria Marinelli

Research output: Contribution to journalArticlepeer-review


Background: Mosaic trisomy 12 is a genetic condition with few cases diagnosed prenatally and postnatally. Phenotypic variability is wide ranging from normal patients to severe congenital anomalies. Case report: A 35-year-old woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Prenatal ultrasound was negative. Cultured amniocytes revealed a karyotype of 47,XX,+12/46,XX. Parents opted for termination of pregnancy at 22 weeks. Postmortem revealed dysmorphic face; hands with broad thumbs and incomplete transverse palmar creases; partial anomalous pulmonary venous return, intestinal malrotation, and bicornuate uterus. Histologically, no anomalies were identified. Cytogenetic analyses on fetal tissues detected mosaic trisomy 12 in thymus, lung, brain, kidney, placenta, and cord blood. Discussion/Conclusion: We report a new case of mosaic trisomy 12 with non-lethal morphological findings not previously described. Although prenatal ultrasound may be negative, genetic counseling should consider minor abnormalities and widespread presence of trisomic cell lines in various internal organs.

Original languageEnglish
JournalFetal and Pediatric Pathology
Publication statusAccepted/In press - 2020
Externally publishedYes


  • mosaic trisomy 12
  • negative ultrasound findings
  • new phenotypic features

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Pathology and Forensic Medicine


Dive into the research topics of 'Mosaic Trisomy 12: Prenatal Diagnosis at Amniocentesis and Molecular Genetic Analysis on Fetal Tissues'. Together they form a unique fingerprint.

Cite this