RED-BLOOD-CELL PHENOTYPES IN THE ALPHA(-CHILDHOOD TO MATURITY() THALASSEMIAS FROM EARLY)

The alpha(+) thalassaemias are the most: common single gene disorders of humans, yet little is known about their haematological characterist ics in childhood, Blood samples have been collected randomly from more than 2000 individuals in village communities in Vanuatu in the South West Pacific and analysed for alpha thalassaemia and associated haemat ological changes. Here we describe the haematological effects of the a lpha(+) thalassaemias from early childhood through to maturity in this population, Mean cell volume (MCV) and mean cell haemoglobin (MCH) le vels in individuals of normal, heterozygous and homozygous genotype di ffered significantly from one another throughout the entire age range (2P < 0.05). In contrast, haemoglobin levels in heterozygous and homoz ygous individuals were well maintained throughout development. Adults of normal genotype attain Hb levels which are indistinguishable from C aucasian reference values, a finding made all the more remarkable give n the high frequency of clinical malaria in this population. It is cle ar from these findings that haematological data are valuable in screen ing for carriers of alpha(+) thalassaemia in this population. MCH is c learly the most sensitive discriminator. None of the homozygous adults tested had an MCH of > 27 pg, whereas < 10% of normals had a value of < 27 pg. These data provide reference values for areas in which the a lpha(+) thalassaemias are common and often confused with iron-deficien cy anaemia.