672 Carbonic Anhydrase (CA-VA) deficiency: an under recognized cause of neonatal hyperammonemia with excellent outcome on proactive management
Bibliographic record
Abstract
Aims Background Neonatal Hyperammonemia is a medical emergency requiring prompt management. The combination of neonatal hyperammonemia, lactic acidosis, ketonuria, and hypoglycemia is pathognomonic for carbonic anhydrase VA (CA-VA) deficiency (figure 1). Methods Objectives To present two siblings with CA-VA deficiency of East Asian ancestry and their clinical course. Results Clinical cases Parents are non-consanguineous from Punjab, India. The first patient is a full-term male who presented with hyperammonemic crisis on the second day of life. The highest ammonia level was 361umol/L (15-55). His metabolic investigations (plasma amino acids, acylcarnitine profile, and urine organic acids) had some overlapping features with a urea cycle disorder and organic acidemia. He was treated initially with nitrogen scavenger therapy and Carglumic acid but eventually needed hemodialysis. DNA analysis on an NGS Urea cycle panel identified two heterozygous variants in CA-VA: c.721G>A, p.Glu241Lys and c.619-?_774+?del. Both variants were considered probably pathogenic. Parental studies showed trans configuration. This confirmed the diagnosis of CA-VA deficiency (JIMD Reports 2020: 1-6). His sibling, also a full-term male, was diagnosed antenatally with CA-VA deficiency based on molecular studies on amniocentesis. He was managed proactively for potential hyperammonemia at birth with IV fluids 10% Dextrose, intralipid 2 gm/kg, and Carbaglu 100 mg/kg BID. The urine organic acids were completely normal. He did not require any further interventions. He was given regular formula and discharged on day five. Currently, the older brother is two years old and the younger brother is 11 months. Neither of them have had any further crisis and both are doing well without any treatment. Conclusion CA-VA deficiency is a recently described rare autosomal recessive inborn error of metabolism which presents with neonatal hyperammonemia with good prognosis if managed appropriately. An isoform, CA-VB’s expression is likely upregulated in the absence of functional CA-VA. CA-VA deficiency should be considered in the differential diagnosis of neonatal hyperammonemia in patients of particularly Indian subcontinent origin as earlier patients have also been described from this region.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".