Paloma Ropero1, Sara Erquiaga2, Beatriz Arrizabalaga2, Germán Pérez3, Silvia de la Iglesia4, María José Torrejón5, Celia Gil6, Cela Elena7, María Tenorio8, Jorge M Nieto1, Félix de la Fuente-Gonzalo1, Ana Villegas1, Fernando-Ataúlfo González Fernández1, Rafael Martínez1. 1. Servicio de Hematología, Hospital Clínico San Carlos, Madrid, Spain. 2. Servicio de Hematología, Hospital Universitario de Cruces, Bilbao, Spain. 3. Servicio de Hematología, Hospital Universitario Marques de Valdecilla, Santander, Spain. 4. Servicio de Hematología, Hospital Universitario de Gran Canaria Dr. Negrín, Las Palmas de Gran Canaria, Spain. 5. Servicio de Análisis Clínicos, Hospital Clínico San Carlos, Madrid, Spain. 6. Servicio de Pediatría, Hospital Clínico San Carlos, Madrid, Spain. 7. Servicio de Pediatría, Hospital General Universitario Gregorio Marañón, Madrid, Spain. 8. Servicio de Hematología, Hospital Universitario Ramón y Cajal, Madrid, Spain.
Abstract
BACKGROUND: β+-Thalassaemia is characterised by reduced production of β chains, which decrease can be caused by mutations in the promoter region (CACCC or TATA box), and is classified as mild or silent depending on the extent of β-globin chain reduction. In both cases, homozygotes or compound heterozygotes for these mutations usually have thalassaemia intermedia. Frequently the diagnosis is made in adulthood or even in old age. A total of 37 alterations in the promoter region have been described so far. AIMS: In this report we describe the mutations found in the promoter region of the β-globin gene in a single hospital in Madrid. METHODS: Between 1998 and 2015, more than 9000 blood samples were analysed for full blood count and underwent haemoglobin electrophoresis and high performance liquid chromatography. Genetic analysis of the β and Gγ-globin genes was carried out by automatic sequencing and, in the case of α genes, by multiplex PCR. RESULTS: 35 samples showed mutation in the promoter region of the β-globin gene, with a total of six different mutations identified: one in the distal CACCC box, two in the proximal CACCC box, three in the ATA box. CONCLUSIONS: Any alterations in the proximal CACCC and TATA boxes lead to a moderate decrease in synthesis of the β-globin chain, which has been demonstrated in cases of thalassaemia intermedia that have presented in the second decade of life with a moderate clinical course. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.
BACKGROUND: β+-Thalassaemia is characterised by reduced production of β chains, which decrease can be caused by mutations in the promoter region (CACCC or TATA box), and is classified as mild or silent depending on the extent of β-globin chain reduction. In both cases, homozygotes or compound heterozygotes for these mutations usually have thalassaemia intermedia. Frequently the diagnosis is made in adulthood or even in old age. A total of 37 alterations in the promoter region have been described so far. AIMS: In this report we describe the mutations found in the promoter region of the β-globin gene in a single hospital in Madrid. METHODS: Between 1998 and 2015, more than 9000 blood samples were analysed for full blood count and underwent haemoglobin electrophoresis and high performance liquid chromatography. Genetic analysis of the β and Gγ-globin genes was carried out by automatic sequencing and, in the case of α genes, by multiplex PCR. RESULTS: 35 samples showed mutation in the promoter region of the β-globin gene, with a total of six different mutations identified: one in the distal CACCC box, two in the proximal CACCC box, three in the ATA box. CONCLUSIONS: Any alterations in the proximal CACCC and TATA boxes lead to a moderate decrease in synthesis of the β-globin chain, which has been demonstrated in cases of thalassaemia intermedia that have presented in the second decade of life with a moderate clinical course. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.