Characterization of deletional and non-deletional alpha globin variants in a large cohort from Spain between 2009 and 2014

The hemoglobinopathies are a group of disorders passed down through families (inherited) in which there is abnormal production or structure of the hemoglobin molecule. They are among the most common inherited diseases around the world. Those that produce abnormal hemoglobin are called structural hemoglobinopathies while thalassemia is another type of disorder that is caused by a defect in the gene production of the globin chains. In a study ambispective comprising 1623 patients, 153 subjects showed an abnormal hemoglobin and 1470 with hypochromic and microcytic anemia, and of these 1470, 23 patients were studied for simultaneously α-thalassemias and structural hemoglobinopathies. Among the α-thalassaemia cases, 1282 cases (87.2%) were deletional α-thalassemia, 172 cases (11.7%) were non-deletional α-thalassemia, and 16 cases (1.1%) were deletional and non-deletional α-thalassamias simultaneously. Thus, approximately 12% of the cases were non-deletional α-thalassaemia. Clinical diagnosis, only 19 severe cases (1 hydrops fetalis and 18 instances of Hb H disease), 1200 thalassamias traits, and 160 thalassaemia silent carriers were recorded within the α-thalassaemia. Regarding structural hemoglobinopathies, there were only 2 cases of hemoglobinopathies with low oxygen affinity and 1 case of hemoglobin M; the remaining 150 were silent hemoglobinopathies. Non-deletional α-thalassaemia represented 12% of all α-thalassemias in our region; the most common deletion in our area was the 3.7-kb deletions, followed by Asian --(SEA) and --(FIL). The alterations responsible for non-deletional α-thalassaemia are most represented by the Hph and Hb Groene Hart and, in the case of structural hemoglobinopathies, Hb Le Lamentin and Hb J-Paris.