Rare Pathogenic ß0-Thalassemia Mutation, Codon 7 (GAG>TAG) (HBB: c.22G>T). Report of the First Two Cases in Albanian Immigrants of Northern Greece.

We report the hematological data of the codon 7 (GAG>TAG (HBB: c.22G>T) mutation for the first time in two Albanian individuals from the region of Elbasan, who underwent genetic testing due to prenatal counseling and diagnosis for ß-thalassemia major (ß-TM) anemia. The phenotype was compatible with a typical ß0-thalassemia (ß0-thal) carrier but the hematological findings of the mutation has not been previously reported. The mutation involves the conversion of codon 7 GAG (Glu) into a translation termination codon (TAG), involving the replacement of guanine by thymine so that no ß chains are produced.

The effect of prolonged administration of hydroxyurea on morbidity and mortality in adult patients with sickle cell syndromes: results of a 17-year, single-center trial (LaSHS).

The aim of this prospective study was to evaluate the long-term efficacy and safety of hydroxyurea (HU) in patients with sickle cell disease (SCD). Thirty-four patients with sickle cell anemia (hemoglobin S [HbS]/HbS), 131 with HbS/beta(0)-thal, and 165 with HbS/beta(+)-thal participated in this trial. HU was administered to 131 patients, whereas 199 patients were conventionally treated. The median follow-up period was 8 years for HU patients and 5 years for non-HU patients. HU produced a dramatic reduction in the frequency of severe painful crises, transfusion requirements, hospital admissions, and incidence of acute chest syndrome. The probability of 10-year survival was 86% and 65% for HU and non-HU patients, respectively (P = .001), although HU patients had more severe forms of SCD. The 10-year probability of survival for HbS/HbS, HbS/beta (0)-thal, and HbS/IVSI-110 patients was 100%, 87%, and 82%, respectively, for HU patients and 10%, 54%, and 66%, for non-HU patients. The multivariate analysis showed that fetal hemoglobin values at baseline and percentage change of lactate dehydrogenase between baseline and 6 months were independently predicted for survival in the HU group. These results highlight the beneficial effect of HU, which seems to modify the natural history of SCD and raise the issue of expanding its use in all SCD patients.

Phenotype and genotype frequency of ß-thalassemia and sickle cell disease carriers in Halkidiki, Northern Greece.

A decade of screening (years 2000 to 2010) for hemoglobinopathies in 3,931 patients was performed at the General Hospital of Poligiros, Halkidiki, Northern Greece. Among the patients examined, 10.8% heterozygotes for ß-thalassemia (ß-thal) were found, as well as 4.1% with sickle cell disease and 1.2% with double ß-thal/Hb S [ß6(A3)Glu→Val] heterozygosity. Iron deficiency was observed in 23.4%. The geographical distribution in the region revealed a substantial incidence of hemoglobinopathies even in mountainous areas. This pattern did not follow the typical distribution according to the malaria hypothesis, as incidence did not dovetail with swamp locations recorded in the past. The HBB gene mutations for 85 patients were also analyzed. Most prevalent in Halkidiki, Northern Greece, was the codon 39 (C>T) mutation (27.1%) followed by the IVS-I-110 (G>A) mutation (22.4%); this was in direct contrast to the current distribution of the same mutations seen in the rest of Greece (Greek National Genetic Database, GNGD). This frequency inversion was statistically significant, with the difference from the GNGD being 20.6% for the IVS-I-110 mutation (p <0.0005) and 7.6% for the codon 39 mutation (p = 0.0238). The history of Halkidiki, denoting a clear example of geographical isolation from the rest of the country, may possibly account for a potentially diverse genetical identity of the disease in this region.

G gamma-196 C-->T, A gamma-201 C-->T: two novel mutations in the promoter region of the gamma-globin genes associated with nondeletional hereditary persistence of fetal hemoglobin in Greece.

The increased level of fetal hemoglobin in nondeletional hereditary persistence of fetal hemoglobin (nd-HPFH) is associated with several single base substitutions in the promoter region of either the (G)gamma- or the (A)gamma-globin genes. In this study, we report two new forms of nd-HPFH found in two unrelated Greek adults with high HbF production (8.6% and 10.2% respectively) and positive for the (G)gamma-158 C-->T substitution. Scanning by DGGE analysis and direct sequencing of the gamma-globin gene 5' promoter region revealed the presence of a (G)gamma-196 C-->T in the first case and an (A)gamma-201 C-->T in the second. These mutations seem to reactivate gamma-genes and cause their high expression in the adult period.

The molecular heterogeneity of beta-thalassemia in Greece.

Beta-thalassemia is the most predominant genetic defect in Greece. In this study, we investigated the heterogeneity and the frequency of beta-thalassemia mutations among 3796 heterozygotes detected in the course of DNA based diagnoses. The diagnostic strategy included Denaturing Gradient Gel Electrophoresis (DGGE), Allele Specific Oligonucleotide Hybridization (ASO), GAP PCR, Restriction Enzyme (RE) analysis and direct sequencing and led to 100% identification of the underlying molecular lesion. Six out of 33 different beta-globin defects identified accounted for more than 91.4% of the total beta-thalassemia chromosomes in Greece. The beta-globin gene mutations cd29 C-->T, IVS-I-2 T-->C, IVS-I-5 G-->T, cd37 G-->A and poly A Kurdish AATAAA-->AATAAG are for the first time reported in Greece, whereas cd7 GAG-->TAG is a new beta(0)-thalassemia mutation detected in an adult man from Albania residing in Greece. Three DNA single nucleotide polymorphisms (IVS-I-85 T-->C, IVS-I-91 C-->T and IVS-I-108 T-->C) were also revealed; among these, IVS-I-85 T-->C and IVS-I-91 C-->T are new and described for the first time worldwide.

Carrier screening and prenatal diagnosis of hemoglobinopathies. A study of indigenous and immigrant couples in northern Greece, over the last 5 years.

Hemoglobinopathies constitute the most frequent monogenic disorders worldwide and thalassemias are the most frequent genetic disorders in Greece. Over a 5-year period (2002-2006), 1,375 couples were screened for hemoglobinopathies and counseled at our Thalassaemia Prevention Unit, Hippokration Hospital, Thessaloniki, Greece. In 148 cases (10.7%), both partners carried an abnormal hemoglobin (Hb) gene and genetic counseling was offered. One hundred out of 116 pregnancies were at-risk of giving birth to an offspring carrying either the homozygous or double heterozygous forms of the mutations under discussion. The remaining 16 pregnancies involved couples who were heterozygous for mutations that did not cause severe clinical disease, and were exempted from prenatal diagnosis. Twenty-six fetuses were found to be homozygotes or double heterozygotes for clinically significant mutations. These couples were informed of the danger of having an affected child but the termination or continuation of the pregnancy was left to the couples to decide. Nevertheless, all the couples preferred to terminate the pregnancies. The National Thalassaemia Prevention Programme has effectively decreased the incidence of thalassemia major and sickle cell syndromes in Greece.