Mosaic trisomy 14 at amniocentesis: prenatal diagnosis and literature review

Intussusception in Mosaic Trisomy 14

Mosaic trisomy 14 is exceptionally rare and was first described in the 1970s with fewer than 100 known liveborn individuals. Information about complications and the natural history of the disease is rare, especially in adult patients. This case illustrates an adult patient with severe functional limitations from mosaic trisomy 14 who presented with abdominal pain and failure to thrive and was subsequently found to have intussusception and severe chronic constipation, which was successfully treated conservatively.

High-level mosaic trisomy 14 at amniocentesis in a pregnancy associated with congenital heart defects and intrauterine growth restriction on fetal ultrasound

OBJECTIVE

We present high-level mosaic trisomy 14 at amniocentesis in a pregnancy associated with congenital heart defects (CHD) and intrauterine growth restriction (IUGR).

CASE REPORT

A 34-year-old, primigravid woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. This pregnancy was conceived by in vitro fertilization and embryo transfer (IVF-ET). Amniocentesis revealed a karyotype of 47,XX,+14[9]/46,XX[13], consistent with 40.9% (9/22 colonies) mosaicism for trisomy 14. Simultaneous array comparative genomic hybridization (aCGH) on the DNA extracted from uncultured amniocytes revealed 61% mosaicism for trisomy 14. Prenatal ultrasound at 22 weeks of gestation showed a malformed fetus with double outlet of right ventricle (DORV), ventricular septal defect (VSD), pulmonary stenosis and severe IUGR with the growth parameters equivalent to 18 weeks of gestation. The pregnancy was terminated at 23 weeks of gestation, and a 278-g female fetus was delivered with facial dysmorphism of hypertelorism, low-set small ears and wide depressed nasal bridge. Quantitative fluorescent polymerase chain reaction (QF-PCR) analysis on the DNA extracted from parental bloods, cord blood, umbilical cord and placenta confirmed a maternal origin of the extra chromosome 14 and excluded uniparental disomy (UPD) 14. The umbilical cord had a karyotype of 47,XX,+14[7]/ 46,XX[13], and the placenta had a karyotype of 47,XX,+14[4]/46,XX[36].

CONCLUSIONS

High-level mosaic trisomy 14 at amniocentesis can be associated with abnormal ultrasound findings of CHD and IUGR.

[Genetic testing and analysis of 2 cases of trisomy 11 mosaicism]

Trisomy 11 mosaicism is clinically rare, for which making diagnostic and treatment decisions can be challenging. In this study, we used noninvasive prenatal testing, chromosome karyotype analysis, chromosome microarray analysis, copy number variation sequencing and fluorescence in situ hybridization for detecting trisomy 11 mosaicism in two cases and provided them with genetic counseling. In one of the cases, the fetus with confined placental mosaicism trisomy 11 presented with severe growth restriction and a placental mosaic level of 44%, and pregnancy was terminated at 25+3 weeks of gestation. In the other case with true low-level fetal mosaicism of trisomy 11, the pregnancy continued after exclusion of the possibility of uniparental disomy and structural abnormalities and careful prenatal counseling. The newborn was followed up for more than one year, and no abnormality was found. Noninvasive prenatal testing is capable of detecting chromosomal mosaicism but may cause missed diagnosis of true fetal mosaicism. For cases with positive noninvasive prenatal testing but a normal karyotype of the fetus, care should be taken in prenatal counseling and pregnancy management.

Low-Level Trisomy 14 Mosaicism: A Carrier of an Isochromosome 14 and a Supernumerary Marker Chromosome 14

Trisomy 14 (T14) mosaicism is a rare chromosomal condition characterised by various clinical features, including developmental delay, growth impairment, and dysmorphism. Here, we report on a 12-year-old female referred for cytogenetic analysis due to short stature. Standard GTG-banding analysis on the patient's peripheral blood revealed mosaic Τ14 in the form of an i(14)(q10) in 3% of cells. Furthermore, a small supernumerary marker chromosome (sSMC) had been detected in the first trimester of pregnancy in chorionic villus sampling. A skin biopsy in the patient revealed the presence of a metacentric sSMC in 100% of cells. Cytogenetic and FISH studies showed that it was a de novo metacentric bisatellited sSMC derived from chromosomes 14 or 22. Oligonucleotide array-CGH using skin cells revealed no copy number variations. Studies for uniparental disomy 14 by microsatellite analysis confirmed biparental inheritance. To the best of our knowledge, this is the second report of a patient with 2 abnormal cell lines involving chromosome 14 in different tissues, one with mosaic T14 in the form of i(14)(q10) and one with an sSMC derived from chromosome 14, present in blood and skin, respectively. A rare mechanism of trisomy rescue events is proposed to explain the presence of the different cell lines in the tissues examined. This case highlights the importance of providing the cytogenetics laboratory with adequate clinical data to test for low mosaicism and analyse different tissues if necessary, thus contributing to the suitable clinical management of the patient.

Umbilical cord accidents and legal implications

Umbilical cord accidents (UCA) are a significant cause of stillbirth. Although infrequent, litigation may occur when there is a poor outcome associated with UCA. With advances in imaging, the ability to identify UCA by ultrasound and magnetic resonance imaging raises awareness of the risk of a poor outcome. Management of a pregnancy with an identified UCA may require more fetal surveillance by both the mother and caregiver. This is especially important if there is a previous history of UCA with or without stillbirth. UCA should be an acknowledged risk which is part of prenatal screening. In the event of a poor outcome associated with UCA, it is recommended that the patient be fully informed of all prenatal information including images. Excellent communication with parents who are looking for answers after a tragic outcome may help to decrease litigation risk.