A Thalassaemia Family in a District Hospital
A couple from a village brings their 3-year-old son to a district hospital. The boy is pale, has a swollen abdomen and has needed a blood transfusion roughly every 5 weeks since he was 8 months old. His report shows Hb 6.8 g/dL, MCV 62 fL, MCH 20 pg, RBC 5.6 million/µL, reticulocytes 4%, serum iron normal and ferritin 380 ng/mL (normal 20–200). Hb electrophoresis: HbF 55%, HbA 5%, HbA2 4%. Both parents are healthy: Hb 11.2 and 10.9 g/dL, MCV 66 and 64 fL, HbA2 5.1% and 5.4%. They are first cousins. The mother asks three questions: will iron syrup help, will the next child also be affected, and should their 8-year-old daughter (Hb 11.6 g/dL, MCV 65 fL, HbA2 5.2%) be worried. A neighbour has advised strong tea with meals to "increase blood".
1. Using the blood counts and electrophoresis, explain the diagnosis. Why is this not iron-deficiency anaemia?
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The child has severe microcytic anaemia (Hb 6.8 g/dL, MCV 62 fL) but with a high red cell count (5.6 million/µL) and normal serum iron - the pattern of a haemoglobin-production defect, not of iron shortage. In iron deficiency the ferritin would be low and the red cell count would tend to fall; here ferritin is 380 ng/mL, above normal, consistent with iron loading from repeated transfusions.
The electrophoresis is decisive: HbF 55% and almost no HbA, meaning β-globin chains are barely made. Excess α chains precipitate in the red cell precursors, causing ineffective erythropoiesis and haemolysis, which is why the spleen and liver enlarge and transfusions are needed. Both parents have low MCV with a raised HbA2 (5.1%, 5.4%) - the typical β-thalassaemia trait. Each parent carries one faulty β allele, and the child inherited one from each, giving β-thalassaemia major. Consanguinity does not create the mutation but makes it more likely that both parents carry the same rare allele from a shared ancestor.
2. What is the chance that the next child is affected, and what is the chance that a healthy sibling is a carrier? Interpret the daughter's report.
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Both parents are carriers, so each pregnancy is an independent 1 in 4 chance of an affected child (two faulty alleles), 1 in 2 of a carrier, and 1 in 4 of a non-carrier. The 25% recurrence risk applies to each future pregnancy; it does not mean one in four children overall. The gene is autosomal, so sons and daughters are equally at risk.
Among children who are healthy, the carrier chance is 2/3, because the affected quarter is excluded from that group. The 8-year-old daughter has Hb 11.6 g/dL with MCV 65 fL and HbA2 5.2%, so she already has the laboratory pattern of β-thalassaemia trait; she is a carrier and does not need treatment. She should be told her status when old enough, and any prospective partner should be screened. If he is also a carrier, each of their children would carry a 25% risk, and prenatal diagnosis can be offered.
3. Evaluate the neighbour's advice about strong tea and the mother's question about iron syrup. Outline the counselling you would give this family.
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Tea contains tannins that bind iron in the gut and reduce absorption. In this child that effect is irrelevant to the anaemia, but the advice is still wrong because it implies a treatment that cannot work. Iron syrup is not merely useless but harmful: with transfusional iron loading (ferritin 380) extra iron can damage the heart, liver and endocrine glands, so iron must be avoided unless a genuine coexisting deficiency is proven. Ferritin should be monitored and iron chelation considered as transfusional load rises.
Counselling should cover: regular transfusions with leucodepleted blood, chelation therapy, folic acid, avoidance of iron tonics and unnecessary supplements, spleen monitoring, and vaccination. Both parents and the daughter should be told they are carriers and that carrier status is not illness. Extended family screening is important in a community with consanguineous marriage, and the couple should be offered genetic counselling about the 25% risk and the option of prenatal diagnosis in future pregnancies.