EP07.12: Dyssegmental dysplasia: clinical, radiological and molecular findings of a challenging antenatal diagnosis in a dizygotic twin pregnancy
Bibliographic record
Abstract
This study reports prenatal sonographic, postnatal clinical and radiological findings and molecular analysis results of a dizygotic twin with dyssegmental dysplasia, Silverman-Handmaker type (DDSH, MIM 224410). Fetal ultrasound findings, clinical course, postnatal skeletal and molecular analyses of heparan sulphate gene 2 (HSPG2) are presented. The patient was a dizygotic (male and female) twin from a consanguineous Pakistani couple. A second trimester anatomical survey raised suspicion of severe skeletal dysplasia in one twin. The mother presented at 35-weeks gestation with antenatal ultrasound findings of the male twin of shortened long bones below the fifth percentile, marked angulation of the femurs, severe scoliosis and short thorax. Postnatal clinical features included widened cranial sutures, short thorax with severe restrictive respiratory failure, severe scoliosis and shortened, bowed long bones. A skeletal survey confirmed findings of thoracolumbar kyphosis with lack of ossification of several vertebral bodies, multiple coronal clefts, moderate shortening, flaring and horizontalisation of the ribs and short, broad tubular bones with bowing and dumbbell appearance of the femora, tibiae and humeri. The patient passed away shortly after birth from respiratory complications. Clinical evolution and phenotype were consistent with DDSH. Molecular testing confirmed the diagnosis by identification of a homozygous mutation in the HSPG2 gene. Although DDSH can theoretically be detected by antenatal diagnosis as early as 13-weeks gestation, it remains a challenging antenatal diagnosis due to its rarity and overlapping phenotype with other severe skeletal dysplasias. The twin pregnancy added additional ultrasonographic and counselling challenges. Molecular testing remains the gold standard for accurate diagnosis of this condition and allows for preimplantation or prenatal diagnosis of this rare autosomal recessive condition for subsequent pregnancies.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
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".