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

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.

Prenatal Diagnosis of Fetal Trisomy 5 Mosaicism with Congenital Pulmonary Airway Malformation Type 3: A Case Report.

Background: Trisomy mosaicism of chromosome 5 is uncommon with few cases described. Case report: A 41-year-old woman underwent ultrasound (US) at 16 weeks, which showed oligohydramnios and intrauterine growth restriction (IUGR). Amniocentesis discovered a karyotype of 47,XX,+5/46,XX. US at 19 weeks disclosed IUGR, enlargement of right side of heart, main pulmonary artery dilatation, and a suspected congenital pulmonary airway malformation (CPAM) in the inferior lobe of the left lung. Due to poor fetal prognosis, the parents opted for legal termination of pregnancy. At postmortem, a wide ventricular septal defect and CPAM type 3 were found. Cytogenetic analyses on fetal tissues detected mosaic trisomy 5 in skin, thymus, kidneys and CPAM. Placenta and fetal peripheral blood revealed normal female karyotype. Discussion/conclusion: These results suggest that if a fetus presents normal phenotypic features, mosaicism may be confined to extraembryonic structures, otherwise, in case of malformations, it may be carried by affected organs.

Copy Number Variation and Rearrangements Assessment in Cancer: Comparison of Droplet Digital PCR with the Current Approaches.

The cytogenetic and molecular assessment of deletions, amplifications and rearrangements are key aspects in the diagnosis and therapy of cancer. Not only the initial evaluation and classification of the disease, but also the follow-up of the tumor rely on these laboratory approaches. The therapeutic choice can be guided by the results of the laboratory testing. Genetic deletions and/or amplifications directly affect the susceptibility or the resistance to specific therapies. In an era of personalized medicine, the correct and reliable molecular characterization of the disease, also during the therapeutic path, acquires a pivotal role. Molecular assays like multiplex ligation-dependent probe amplification and droplet digital PCR represent exceptional tools for a sensitive and reliable detection of genetic alterations and deserve a role in molecular oncology. In this manuscript we provide a technical comparison of these two approaches with the golden standard represented by fluorescence in situ hybridization. We also describe some relevant targets currently evaluated with these techniques in solid and hematologic tumors.