Projected number of pregnancies at risk of Hb H disease
| Type | MCV 80–85 fL* | <80 fL† |
|---|---|---|
| *Calculated using values from table 1 and a prevalence rate11 of 82/1800 for (−−SEA) as follows: for deletional Hb H disease, 70 000 births/year × (31/1727 × 82/1800); for non-deletional Hb H disease, 70 000 × (1/1727 × 82/1800). | ||
| †Calculated using values from Lau et al,11 where the prevalence rate of the (−SEA) deletion is 82/1800, the prevalence rate of single α gene deletion is 9/1800, and the prevalence rate of single non-deletion α gene mutations is 0/1800: for deletional Hb H, 70 000 × (82/1800 × 9/1800); for non deletional Hb H, 70 000 × (82/1800 × 0/1800). | ||
| MCV, mean corpuscular volume. | ||
| Deletional | 57 | 16 |
| Non-deletional | 2 | 0 |