Hemoglobin "Pylos": Study of a Hemoglobinopathy Resembling Thalassemia in the Heterozygous, Homozygous and Double Heterozygous State

Eight Greek families are reported in which an hereditary hemoglobin abnormality was present. The abnormal hemoglobin is provisionally called Hgb "Pylos" (= Lepore?) and its properties are described. The pattern of inheritance suggests a one gene effect.

In the heterozygous state the abnormality manifests itself by the presence of low amounts of Hgb "Pylos", low amounts of Hgb A₂ and mild increase of Hgb F together with quantitative and qualitative alterations of the red cells as observed in thalassemia trait. In one homozygous individual, complete absence of Hgb A and Hgb A₂ as well as very high amounts of Hgb F were observed, together with a clinical and hematologic picture resembling overt thalassemia. The combination with A₂-thalassemia was observed in five cases and manifested itself by a clinical and hematologic picture of rather moderately severe thalassemia, by complete absence of Hgb A and by predominance of Hgb F. In both the homozygote and the double heterozygotes the amount of Hgb "Pylos" was within the range found for heterozygotes. The findings are discussed and it is concluded that the abnormal gene is allelomorphic to the gene controlling synthesis of β-chains; however, it appears to affect concomitantly the synthesis of δ-chains. The possible interpretations of this double effect are presented.