Molecular heterogeneity of β‐thalassaemia in a Spanish population from the area centre of Spain

Letters to the Editor P-Thalassaemia is a worldwide inherited disorder characterized by a reduction or complete absence of P-globin expression. The long frequency of thalassaemia is found in areas endemic for malaria, which includes the Mediterranean, Africa and Southeast Asia (1). More than 120 P-thalassaemia mutations have been described (2). However, each population group displays its own mutations. In the Mediterranean area more than 30 different mutations have been described, although only a few, generally 5, are responsible for almost 90% of the mutations. The incidence of heterozygous P-thalassaemia is high in Spain and may even reach 5% of the population in some regions (3-5). However, it does not constitute a serious public health problem as it is in some Mediterranean basin countries, such as Italy and Greece (6,7), since less than 70 cases of homozygote P-thalassaemia have been recorded in Spain. Spain is a geographic area whose racial characteristics have been formed by emigration, over the centuries, from numerous people that colonized the Iberian Peninsula. The Moslem occupation of the Iberian Peninsula, which took place in AD 713, continued until 1492. After that, the population movements were scant except for those produced in the last century by the internal shifting of the Spanish inhabitans from village settlements to the industrial nucleus of large industrial areas in cities. Molecular studies carried out in the Spanish population have manifested that the mutations correspond to those previously described in other countries of the Mediterranean basin (4, 6, 8). In this study a total of 134 alleles relating to 131 patients from Madrid, Castilla la Mancha and Castilla y Le6n has been studied; of them, 9 had P-thalassaemia major (12 alleles, since there were 3 pairs of brothers) and 122 unrelated patients the P-thalassaemia trait. Blood samples were collected in EDTA. Most of these (122 patients) were heterozygous Pthalassaemia with mild anaemia, microcytosis and hypochromia and elevated levels of Hb A,, and 9 eitv of 13 I onhorn l-tha the lassa area .e rnia