Bibliographic record
Abstract
Introduction: The discovery of PHOX2B as the disease defining gene in congenital central hypoventilation syndrome was based on its known effect on the development of the autonomic nervous system. PHOX2A is a paralogue gene that is similarly involved in the development of the autonomic nervous system. We describe the case of a late preterm infant with severe central sleep apnea who was found to have a variant of unknown significance in the PHOX2A gene. Case: An 11-day old boy was admitted to a children's hospital for workup of intermittent desaturations and hypercapnia. He was conceived by in vitro fertilization with a donor ovum. The antenatal period was complicated by intrauterine growth restriction and preeclampsia with marginal cord insertion. The infant was born at 36 +0 weeks gestational age by vacuum assisted vaginal delivery. APGAR scores were 4, 7, and 9 at 1, 5, and 10 minutes respectively. Birth weight was 2250 grams (13 th percentile). He received 12 hours of continuous positive airway pressure immediately following birth for presumed transient tachypnea of the newborn. He was discharged on the third day of life and subsequently found to have poor weight gain, intermittent desaturations, and hypercapnia of 56-59 mmHg on capillary blood gas. Chest x-ray, echocardiogram, and septic work up were unremarkable. Baseline polysomnogram on day of life 13 revealed a central apneahypopnea index of 86 events/hour with similar frequency in quiet and active sleep. The oxygen saturation nadir was 66% with a desaturation index of 88 events/hour. Longest apnea duration was 20 seconds. A screening work up including thyroid studies, brain MRI, video electroencephalogram, brainstem evoked potentials, and a metabolic screen were unremarkable. Treatment with supplemental oxygen and oral caffeine stabilized oxygen saturations and carbon dioxide levels. Genetic testing revealed a heterozygous variant of unknown significance in the PHOX2A gene (c.88C>A). Caffeine was discontinued at one month of life and supplemental oxygen was weaned as an outpatient. He is growing well and meeting normal developmental milestones at six months of age. Discussion: This case describes an infant with severe central sleep apnea and a heterozygous variant of unknown significance in the PHOX2A gene. Homozygous mutations in PHOX2A are reported to cause congenital fibrosis of the extraocular muscles type 2, but it is unknown whether the gene contributes to the control of breathing. Future studies may elucidate whether PHOX2A is implicated in alveolar hypoventilation and central sleep apnea.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.002 | 0.001 |
| 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".