Basic genetics and patterns of inheritance
Hung N. Winn, Frank A. Chervenak, Roberto Romero in Clinical Maternal-Fetal Medicine Online, 2021
Trisomy 18 (Edward syndrome) is a much less common autosomal trisomy, seen in approximately 1 in 7000 liveborn infants (21). It has been estimated that at least two-thirds of trisomy 18 conceptuses are lost by spontaneous abortion. Trisomy 18 is caused by the presence of three copies of the number 18 chromosome, again arising by nondisjunction in meiosis I or meiosis II.
Prenatal Diagnosis and Screening for Aneuploidy
Vincenzo Berghella in Obstetric Evidence Based Guidelines, 2022
With full trisomy 18, the recurrence risk is empirically 1% or the maternal age-related risk. With Robertsonian translocation, parental chromosomes should be analyzed, with genetic counseling regarding specific future risks. There are other rare translocations leading to trisomy 18.
Management of Dying
Hazel E McHaffie, Peter W Fowlie, Robert Hume, Ian A Laing, David J Lloyd, Andrew J Lyon in Crucial Decisions at the Beginning of Life, 2018
When invasive treatment is being or has been withdrawn, dignity both in life and in death is an important factor. There seems to be little value to the parents in persisting with procedures which appear to compromise that state. As the mother of a child with trisomy 18 wrote:
Assessment of foetal ventriculomegaly from prenatal to early postnatal period: a single-centre retrospective cohort study
Published in Journal of Obstetrics and Gynaecology, 2022
Nurullah Cihan Sohret, Ayse Neslihan Tekin, Ozge Surmeli Onay, Kamuran Suman, Ozge Aydemir, Melih Velipasaoglu
Other than infections, probability of chromosomal anomalies should be kept in mind in foetal VM cases. Graham et al. (2001) found aneuploidy in 14.2% of mild and moderate VM cases and 17.4% in severe VM. Similarly, Gezer et al. (2014) in their study with 140 VM cases detected chromosomal anomalies in seven. Regarding the genetic diagnosis of foetal VM cases, a study including 231 isolated VM cases in China found that the most common chromosomal anomaly was Trisomy 21 followed by 45 + X (Turner Syndrome; Zhao et al. 2018). In our study group, Trisomy 21 was detected in two cases and Trisomy 18 in one case. In the case of Trisomy 18, pericardial and pleural effusions, coroid plexus cysts, and a single umbilical artery in the cord were detected. One of the Trisomy 21 cases had no other signs; while the other exhibited pelvicaliectasis and an intracardiac hyperechogenic focus in the left ventricule. In all three cases with chromosomal abnormalities, the VM was mild.
Let It Be: The Evolving Standard of Care for Trisomy 18
Published in The American Journal of Bioethics, 2020
Michael Kochan, Lucy Davidoff, Alison Falck
Trisomy 18 is the second most common aneuploidy after trisomy 21. Thirty years ago and beyond, trisomy 18 was considered a lethal anomaly, with a median survival of days and no survival to 1 year of age (Embleton et al. 1996). The long-standing consideration of this condition as lethal may have contributed to a self-fulfilling prophecy, as most infants not afforded life support ultimately died. In the last 20 years, there has been a shift in the approach to treatments that may be offered to parents of infants with trisomy 18. While not all medical providers agree with this approach, more infants with trisomy 18 have received intensive care, including surgery, and thus more have survived. Although mortality remains high despite the provision of intensive medical and surgical care, the mortality rate for infants with trisomy 18 is not 100%. More recent literature documents that 8–25% of infants with trisomy 18 may reach their first birthday, and up to 10% are reported to survive up to several years (Kosho et al. 2006; Kukora et al. 2019). Perhaps, more accurately, this condition can be described as life-limiting, rather than lethal (Kukora et al. 2019).
Prenatal diagnosis of cystic hygroma cases in a tertiary centre and retrospective analysis of pregnancy results
Published in Journal of Obstetrics and Gynaecology, 2022
Sureyya Saridas Demir, Erkan Cagliyan, Derya Öztürk, Samican Özmen, Sabahattin Altunyurt, Tufan Çankaya, Elcin Bora
The pregnant women included in the study were divided into two according to their gestational weeks. The numbers of chromosomal abnormalities found in foetuses according to these groups were calculated and the results obtained are given in Table 2. According to these results, trisomy 18 was found in five foetuses of 19 pregnancies under 14 weeks and trisomy 21 in two foetuses. In addition, chromosomal abnormality was not detected in the foetuses of seven of the pregnancies below 14 weeks and chromosomal analysis could not be performed because five pregnant women refused invasive intervention. Trisomy 18 was detected in the foetus of three of the pregnancies over 14 weeks and monosomy X and trisomy 21 in the foetus of 1. Chromosomal abnormality was not detected in the foetuses of three pregnancies over 14 weeks and chromosomal analysis could not be performed because two pregnant women refused the invasive procedure.
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