Haemoglobin CO-Arab Mimicking HbSS and HbSC: A Case Report
Bibliographic record
Abstract
Introduction: Haemoglobin C-O Arab is an infrequent condition with limited literature documentation. The underlying mutations in HbC and HbO-Arab affect positions 6Glu → Lys and 121Glu → Lys of the Beta-globin gene, respectively. Interestingly, when both HbC and HbO-Arab are inherited, the individual has the same mutations (Glu → Lys) at different positions (6 and 121) of the same globin chain. The consequences of these interactions make this a unique and enigmatic condition. Aim: To report a case of HbCO-Arab mimicking HbSS in a patient. Method: A case report of the patient’s clinical note. Results: A 26-year-old Fulani lady presented to the Haematology Day Care (HDC) due to varying Hb electrophoresis results. She gave a history of recurrent headaches, occasional bone pains and easy fatiguability. However, no history of jaundice or blood transfusions. Hb electrophoresis done at 6 years was suggestive of HbSS. No history suggestive of sickle cell complications except for a history of parapneumonic effusions at the age of 21 years. Two of her siblings are said to be patients living with sickle cell disease. There was no jaundice, pallor, cyanosis or sickle cell habitus. Four previous Hb electrophoreses using alkaline media revealed a single band in the S position except for one, which showed two bands in the S and C regions. A repeat upon presenting to the unit showed a single band at the S region on alkaline electrophoresis. Haematocrit over three years ranged from 32.7% to 40.8% Given the atypical presentation (history and physical examination) and discrepancies in electrophoresis results, HPLC was done. The presence of an unknown band further added to the diagnostic dilemma. The sample was then sent to the Synnovis Special Haematology Laboratory at Guys and St Thomas Hospital, London, for further testing. Sanger sequencing was performed on the beta-globin genes. This demonstrated compound heterozygous mutations for Hb C due to the HBB;c.19G>A and Hb O-Arab due to the HBB;c.364G>A mutations. Conclusion: A high index of suspicion and domesticated diagnostic algorithms are needed, especially in resource-constrained settings.
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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 | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.004 | 0.003 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.006 | 0.004 |
| Science and technology studies | 0.004 | 0.003 |
| Scholarly communication | 0.003 | 0.003 |
| Open science | 0.001 | 0.003 |
| Research integrity | 0.007 | 0.004 |
| Insufficient payload (model declined to judge) | 0.004 | 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".