RESUMO
Hemoglobinosis H is the severest alpha-thalassemia compatible with life. The clinical manifestation seems to be different regarding to the genotype. The present paper aims to provide to hematological and molecular data related to three patients suffering from hemoglobinosis H alpha thalassemia and their family. The clinical and biological profiles appear to be similar to those observed in thalassemia intermedia with mild hemolytic microcytic anemia. The diagnosis was based on decreased Hb A2 level [< 2%] and the presence of Hb H at an amount ranging from 10 to 30%. Two different molecular defects were observed. The genotypes were an association of two types of deletion [--MEDI an alpha [3.7]] and two point mutations [alpha[snt] and alpha t], The correlation phenotype / genotype showed that non-deletional Hb H is more severe than deletional forms. Detection of athalassemia trait remains difficult, it's detection is yet a matter of exclusion diagnosis based on the observation of isolated microcytosis with normal or limited Hb A2 levels with a normal iron state. Molecular study is a powerful tool for the diagnosis of such alpha cases