title: Non-mosaic trisomy 20 of paternal origin in chorionic villus and amniotic fluid also detected in fetal blood and other tissues.
abstract: Trisomy 20 mosaicism is a common abnormality found in prenatal diagnosis. Its clinical significance remains unclear since approximately 90-93% of cases result in normal phenotype. Only 5 cases of non-mosaic trisomy 20 in amniotic fluid culture surviving beyond the first trimester have been reported. Moreover, trisomic cells are generally not detectable in blood and have only been reported in three cases. We present a case of non-mosaic trisomy 20 found in chorionic villi sample and amniotic fluid culture in a fetus with minor abnormalities not detected by ultrasound examination. Pathological examination of the fetus only revealed right pulmonary isomerism and camptodactily, and no major malformations were disclosed. Trisomic lineage was also detected in fetal blood, kidney, skin and brain tissue cultures. Molecular analysis revealed that the extra chromosome 20 was originated in paternal meiosis. To our knowledge, we report the first prenatal case of non-mosaic trisomy 20 of paternal origin that has been confirmed in several fetal tissues, including blood, in a fetus with minor malformations not detected prenatally.
authors.affiliation: Servei de Bioquímica i Genètica Molecular, Hospital Clínic, Villarroel 170, 08036 Barcelona, Spain; CIBER de Enfermedades Raras (CIBERER), Barcelona, Spain. cmorales@clinic.ub.es
authors.forename: Carme
authors.initials: C
authors.lastname: Morales
authors.forename: Esther
authors.initials: E
authors.lastname: Cuatrecasas
authors.forename: Irene
authors.initials: I
authors.lastname: Mademont-Soler
authors.forename: Núria
authors.initials: N
authors.lastname: Clusellas
authors.forename: Emma
authors.initials: E
authors.lastname: Peruga
authors.forename: Vicenç
authors.initials: V
authors.lastname: Català
authors.forename: Carles
authors.initials: C
authors.lastname: Garrido
authors.forename: Montserrat
authors.initials: M
authors.lastname: Milà
authors.forename: Anna
authors.initials: A
authors.lastname: Soler
authors.forename: Aurora
authors.initials: A
authors.lastname: Sánchez
mesh_terms: D000328:Adult; D000653:Amniotic Fluid / Q000166:cytology*; D002478:Cells, Cultured; D015193:Chorionic Villi Sampling; D002869:Chromosome Aberrations; D002890:Chromosomes, Human, Pair 20 / Q000235:genetics*; D005260:Female; D005312:Fetal Blood / Q000166:cytology*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D009030:Mosaicism; D010375:Pedigree; D011247:Pregnancy; D011296:Prenatal Diagnosis; D014314:Trisomy / Q000235:genetics*