[Combined alpha and beta thalassemia in a Chinese family in The Netherlands].

In a Chinese family living in The Netherlands alpha 0- and beta-thalassaemia occur singly and in combined form. All members of the family are moderately anaemic and show the characteristic haematological abnormalities of thalassaemia carriers. The nature of the alpha 0-thalassaemia defect was shown at the molecular level to be a deletion of the South East Asian type, which removes about 20 kb of DNA spanning both alpha genes in cis. The chromosome carrying the beta-thalassaemia mutation was identified using RFLPs (restriction enzyme fragment length polymorphisms). The combined heterozygosity for alpha 0- and beta-thalassaemia results in a phenotype virtually indistinguishable from heterozygous beta-thalassaemia, except for the almost balanced globin chain synthesis.