An Abnormal Haemoglobin (Lepore/Cyprus) Resembling Haemoglobin-Lepore and its Interaction with Thalassaemia

Haemoglobin Lepore trait: haematological and structural studies on the Italian population

Haematological data on 59 heterozygotes for haemoglobin (Hb) Lepore and 10 double heterozygotes for Hb Lepore and beta thalassaemia from 36 Italian families are reported. The red cell indices are defined and compared with those of groups of non-thalassaemic and beta thalassaemic subjects of comparable number, age and sex distribution. The relative level of each haemoglobin fraction and the absolute production of single polypeptide chains are calculated in order to compare the expression of the non-alpha chain genes in Hb Lepore trait and beta thalassaemia. Structural studies demonstrate that the haemoglobin Lepore is of the Boston type (delta 87 beta 116) in all subjects, confirming that this type of fusion variant is probably the only one which occurs in Mediterranean populations. The distribution and incidence of the Lepore haemoglobinopathy are discussed.

Hemoglobins Lepore and anti-Lepore

The structure, properties, genetics, and clinical and biochemical expression of hemoglobins Lepore (deltabeta) and anti-Lepore (betadelta) are described. In addition to the three Lepore variants (Lepore Hollandia, Lepore Baltimore and Lepore Washington) at least four anti-Lepore variants (Miyada, P Nilotic (P Congo), Coventry and Lincoln Park) are known at the present time. All known hemoglobins Lepore and anti-Lepore are products of non-homologous crossing-over between the delta and the beta genes. Although the Hb Lepore condition is expressed phenotypically and clinically as beta thalassemia, the presence of about 10% of Hb Lepore distinguishes the condition hematologically from beta thalassemia. Data on the hematological and biochemical expression of this hemoglobinopathy are presented. In contrast to the anemia in the Lepore condition, there is no phenotypic evidence of thalassemia in persons with hemoglobin anti-Lepore, because no beta chain deficiency accompanies the latter condition. Although no adequate explanation has been advanced concerning the factors which maintain a low synthesis of the Lepore and anti-Lepore chains, it has been suggested that multiple rare codons may introduce rate-limiting steps or that the deltabeta and betadelta mRNAs may be unstable. Data on the geographical distribution and structural identification of Hb Lepore are presented.

Haemoglobin LeporeBoston in a Turkish family

Haemoglobin Lepore was demonstrated in four members of a Turkish family. It was found in the heterozygote state and was associated with erythrocyte morphology similar to that observed in the beta thalassaemia trait. The average concentration of haemoglobin Lepore was 8.1% of the total haemoglobin. Structural analysis showed that the Lepore haemoglobin was the LeporeBoston type. This is the first reported instance of the occurrence of haemoglobin Lepore in Turkey.

Haemoglobin Lepore in Cyprus

Structural analysis documented the presence of haemoglobin LeporeWashington (=LeporeBoston) in a Greek Cypriot family and provided further evidence that, of the various types of Lepore mutants, only one is common in the Mediterranean area. Two individuals in this family were heterozygous for both Hb Lepore and beta thalassaemia, but they exhibited striking differences in the clinical severity and course of the disease. The data illustrate that additional environmental or genetic factors play roles in determining or modifying the pathophysiological consequences of highly specific molecular defects and, thus, their ultimate clinical phenotypes.

Haemoglobin Lepore Boston and elliptocytosis in a family of Indonesian-German ancestry

A family is presented in which Hb Lepore Boston was found in six individuals over three generations. The gene must have had its origin either in Java (Indonesia) or in what is now the Federal Republic of Germany. The haemoglobin was characterized by amino-acid analysis of the six tryptic peptides that have a different composition in the beta- and the delta-chain. The ratio of glycine to alanine in position 136 of the fetal haemoglobin, which was somewhat raised in the Hb Lepore carriers, averaged 31:39. In addition an elliptocytosis gene was found, which was inherited independently from Hb Lepore; the simultaneous presence of elliptocytosis in three family members did not seem to aggravate the mild anaemia caused by Hb Lepore.