Prenatally detected trisomy 20 mosaicism
Bibliographic record
Abstract
BACKGROUND: Trisomy 20 is one of the more common mosaic trisomies detected on amniocentesis and presents with a normal outcome in over 90% of reported cases. Trisomic cells are almost never confirmed in newborn blood and are only rarely found in other fetal or placental samples. Nonetheless, some abnormal outcomes have been reported, including unexplained fetal demise, intrauterine growth restriction, and multiple congenital anomalies. Because of the lack of molecular studies on such cases, it is unknown whether the origin of trisomy or presence of uniparental disomy (UPD) could have some influence on outcome. METHODS: We present data on six cases of trisomy mosaicism, two detected by chorionic villous sampling (CVS) and four by amniocentesis (AF), submitted to our laboratory for molecular studies. RESULTS AND CONCLUSIONS: A meiotic origin of the trisomy could be confirmed in only one of these cases. In addition, uniparental disomy was excluded in all four cases for which parents were available for testing. The four cases with low levels of trisomy in amniotic fluid (0%, 10%, 11%, and 12%) were associated with a normal outcome. The remaining two cases of trisomy 20 had high levels of trisomy in amniotic fluid (96% and 58%) and had abnormal outcomes (developmental delay in one and stillbirth with IUGR and severe oligohydramnios in the other). Including previously published cases, there is a clear association with the level of trisomy and outcome, with only 4% abnormal outcomes when <40% trisomic cells were detected. Higher levels of trisomy were also observed in male fetuses as compared to female fetuses (p = 0.01); however, there were no sex differences in frequency of abnormal outcomes.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".