Haemoglobinopathies.

The inherited haemoglobinopathies are a heterogeneous group of recessive disorders that include the thalassaemias and sickle cell disease. Nearly a thousand mutant alleles have now been characterized. The mutations are regionally specific and in most cases the geographical and ethnic distributions have been determined providing the foundation for a programme of control through screening, genetic counselling and prenatal diagnosis. The main requirements for methodologies providing molecular diagnosis are speed, cost, convenience and the ability to test for multiple mutations simultaneously. For beta-thalassaemia mutations the procedures that meet these requirements are the amplification refractory mutation system and the reverse dot-blot hybridization system. For alpha-thalassaemia the technique of gap PCR is useful for targeting specific deletion mutations but Southern blotting remains the standard diagnostic test.