Nicolina Giagu

Hyperbilirubinaemia in heterozygous β‐thalassaemia is related to co‐inherited Gilbert's syndrome

The reasons why heterozygotes for β‐thalassaemia have considerable variation in serum bilirubin levels are unkown. High levels of bilirubin could be related to the co‐inherited Gilberts syndrome, determined either by mutations of the coding region or by variation in the A(TA)nTAA motif of the promoter of the bilirubin UDP‐glucuronosyltransferase gene (UGT‐1). We sequenced the coding and the promoter region of UGT‐1A or characterized the A(TA)nTAA motif of the promoter by denaturing gel electrophoresis of radioactive amplified products. The results were correlated with bilirubin levels in 49 β‐thalassaemia heterozygotes for codon 39 (CAG → TAG) nonsense mutation. 21 normal individuals and 32 unrelated patients with Gilberts syndrome served as controls. The coding sequence region of the UGT‐1A was normal. Five β‐thalassaemia heterozygotes, who were homozygous for the extra (TA) bases in the A(TA)nTAA element of the promoter of UGT‐1A, the configuration present in homozygosity in Gilberts syndrome, had higher bilirubin levels compared to those with the (TA)6/(TA)7 or (TA)6/(TA)6 configurations.

Association of α globin gene quadruplication and heterozygous β thalassemia in patients with thalassemia intermedia

The degree of the globin chain imbalance is the pathogenetic clue to the clinical phenotype of thalassemia syndromes. This paper reports a duplication of the α globin gene locus in a group of hetereozygous β-thalassemia patients with the unexplained phenotype of thalassemia intermedia. Ten patients with thalassemia intermedia with variable severity and apparent simple heterozygosis for β0 39 C>T nonsense mutation were submitted to clinical, hematologic and molecular studies. The presence of an unknown molecular defect (silent β-thalassemia) unlinked to the β cluster interacting with the heterozygous β thalassemia, was previously postulated in these families. Analysis of the α globin gene cluster with PCR-based methods (MLPA, GAP-PCR, digestion with restriction enzymes) detected complex rearrangements in the α cluster. A duplication of the α globin gene locus, including the upstream regulatory region, was present in all the patients, associated in some of them with deletion or non-deletion α thalassemia. The variability of the clinical phenotype correlates with the degree of the globin chain imbalance. The presence of α globin cluster duplication should be considered in patients heterozygote for β-thalassemia with thalassemia intermedia phenotype and in the carriers of suspected silent β thalassemia.

Clinical and molecular analysis of haemoglobin H disease in Sardinia: haematological, obstetric and cardiac aspects in patients with different genotypes

In this study, 251 Sardinian patients (187 adults and 64 children) with haemoglobin (Hb) H disease were evaluated. Two‐hundred and sixteen patients (86%) had the deletional type (‐ ‐/‐α) and 36 (14%) patients had the non‐deletional type (‐ ‐/αNDα). A clear genotype–phenotype correlation was found, with the non‐deletional type more severe than the deletional type. Diagnosis of Hb H disease was incidental in about 60% of cases. Aplastic crises due to B19 parvovirus infection were found in five patients (2·1%), while 23 patients (9·6%) experienced one or more haemolytic crises. Nineteen patients with Hb H received sporadic red blood cell transfusions and three patients were repeatedly transfused. Forty‐seven of 61 married women (77%) had 82 pregnancies. In children, mean serum ferritin was 87 ±92 μg/l and in adults, was 192 ± 180 μg/l in females and 363 ± 303 μg/l in males. For the 98 male patients, a significant correlation was found between ferritin values and age (r2 = 0·33, P < 0·0001). In the Sardinian population, Hb H disease needs regular monitoring for early detection and treatment of possible complications, such as worsening of anaemia that may require red cell transfusion, cholelithiasis and iron overload.

Responsiveness to oral iron and ascorbic acid in a patient with IRIDA.

Mutations in TMPRSS6 gene cause iron-refractory iron deficiency anemia, a rare autosomal recessive disorder characterized by hypochromic microcytic anemia not responsive to oral iron therapy and partially responsive to parenteral iron administration. Here we report a female infant homozygous for a loss of function mutation in TMPRSS6 gene, who responded to oral iron therapy when supplemented with ascorbic acid.

Delayed fetal hemoglobin switching in subjects with KLF1 gene mutation

Variations at the KLF1 gene have been associated with a series of human erythroid phenotypes including the In-(Lu) phenotype, hereditary persistence of fetal hemoglobin, congenital dyserythropoietic anemia, borderline HbA(2) and increased red blood cell protoporphyrin. Natural mutations have shown that KLF1 regulates gamma globin gene expression and its role in the switching from fetal to adult globin expression has been suggested by experimental studies. In this paper we report that subjects with S270X KLF1 mutations show a decrease of HbF levels with increasing age, supporting in vivo the role of KLF1 in hemoglobin switching in humans.

Differences in the erythropoiesis-hepcidin-iron store axis between Hemoglobin H disease and β-thalassemia intermedia

Congenital anemias due to ineffective erythropoiesis, such as sideroblastic anemia, congenital dyserythropoietic anemia and β-thalassemia intermedia (TI), are frequently associated with increased dietary iron absorption and progressive iron loading, and are therefore defined as “iron loading

A decisional algorithm to start iron chelation in patients with beta thalassemia

Since the implementation of deferrioxamine for the treatment of thalassemia major, it has been customary to initiate chelation after the first 10–20 transfusions or when serum ferritin reached over 1000 mcg/L.[1][1] However, in non-chronically-transfused thalassemia patients, ferritin

Red cell pyruvate kinase deficiency in Southern Sardinia.

Pyruvate kinase (PK) deficiency is the most frequent red cell enzymatic defect responsible for hereditary non-spherocytic hemolytic anemia. The clinical picture is quite variable and the reasons of this variability have been only partially clarified. We report the clinical description and the extended molecular analysis in 3 PK deficient patients with clinical phenotype of variable severity. We studied the clinical and hematological aspects of 3 patients and analyzed the following genes: pyruvate kinase-R, glucose-6-phosphate-dehydrogenase, α-globin, uridindiphosphoglucuronil transferase and HFE. One patient (A) with a severe clinical picture resulted homozygote for exon 8 nt994A substitution, the other 2 (brothers) were compound heterozygotes for exon 8 nt994A and exon 11 nt1456T mutation. One of the two brothers with a more severe phenotype coinherited also had G6PD deficiency, while both had microcytosis due to the homozygosity for the non-deletional form of α-thalassemia ATG→ACG substitution at the initiation codon of the alpha2 globin gene. Our results suggest that extended molecular analysis is useful for studying how several interacting gene mutations contribute to the clinical variability of pyruvate kinase deficiency.