46,XY/46,XY Chimerism: Prenatal Presentation and Postnatal Outcome
Bibliographic record
Abstract
BACKGROUND: Human chimerism is rare, and most prevalent with discordant chromosomal sex. We report a male 46,XY/46,XY chimera, born through a spontaneously conceived pregnancy to a healthy 32-year-old G1P0 Indian, African, and Scottish female and her 34-year-old healthy Chinese partner. The prenatal presentation and postnatal outcomes are described. METHODS: A prenatal cell-free DNA screening test, amniocentesis with QF-PCR and SNP microarray, and postnatal microarray and FISH study on peripheral blood, placenta, and umbilical cord were used to evaluate chimerism. RESULTS: The prenatal cell-free screening test revealed high risk for triploidy/vanishing twin, but there was no confirmation from early ultrasound. Subsequent QF-PCR on amniocytes showed a profile suggestive of a tetragametic chimera. G-banding showed a 46,XY karyotype. A SNP microarray detected two copy number gains of uncertain significance on chromosome 6q, derived from the father who was a balanced carrier of ins(6;11). A postnatal microarray and FISH study confirmed the presence of two cell lines, each with a 46,XY complement but with different submicroscopic structural changes including recombinant and insertion changes. Clinical evaluations of the child at birth and 8 weeks of age were coordinated to detect the presence of chimeric symptoms. CONCLUSION: With a confirmed incidental finding of 46,XY/46,XY chimerism, we present that underlying same-sex chimerism may be under-recognized.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".