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Background Defective synthesis of the α-globin chain due to mutations in the alpha-globin genes and/or its regulatory elements leads to alpha thalassaemia syndrome. Complete deletion of the 4 alpha-globin genes results in the most severe phenotype known as haemoglobin Bart’s, which leads to intrauterine death. The presence of one functional alpha gene is associated with haemoglobin H disease, characterised by non-transfusion-dependent thalassaemia phenotype, while silent and carrier traits are mostly asymptomatic. Main body Clinical manifestations of non-deletional in alpha thalassaemia are varied and have more severe phenotype compared to deletional forms of alpha thalassaemia. Literature for the molecular mechanisms of common non-deletional alpha thalassaemia including therapeutic measures that are necessarily needed for the understanding of these disorders is still in demand. This manuscript would contribute to the better knowledge of how defective production of the α-globin chains due to mutations on the alpha-globin genes and/or the regulatory elements leads to alpha thalassaemia syndrome. Conclusion Since many molecular markers are associated with the globin gene expression and switching over during the developmental stages, there is a need for increased awareness, new-born and prenatal screening program, especially for countries with high migration impact, and for improving the monitoring of patients with α-thalassaemia.

Background: Over 1900 mutations have been identified in the cystic fibrosis conductance transmembrane regulator gene, including single nucleotide substitutions, insertions, and deletions. Unidentified mutations may still lie in introns or in regulatory regions, which are not routinely investigated, or in large genomic deletions, which are not revealed by conventional molecular analysis. The apparent homozygosity for a rare, cystic fibrosis conductance transmembrane regulator mutation screened by standard molecular analysis should be further investigated to confirm if the mutation is in fact homozygous. We describe a patient presenting with an apparent homozygous S4X mutation. Case presentation: A 13-year-old female patient of African descent with clinical symptoms of classic cystic fibrosis and a positive sweat test (97 mEq/L, diagnosed at age 3 years) presented with pancreatic insufficiency and severe pulmonary symptoms (initial lung colonization with Pseudomonas aeruginosa at age 4 years; forced vital capacity: 69%; forced expiratory volume: 51%; 2011). Furthermore, she developed severe acute lung disease and recurrent episodes of dehydration requiring hospitalization. The girl carried the CFTR mutation S4X in apparent homozygosity. However, further analysis revealed a large deletion in the second allele that included the region of the mutation. The deletion that we describe includes nucleotides 120–142, which correspond to a loss of 23 nucleotides that abolishes the normal translation initiation codon. Conclusion: This study reiterates the view that large, cystic fibrosis conductance transmembrane regulator deletions are an important cause of severe cystic fibrosis and emphasizes the importance of including large deletions/duplications in cystic fibrosis conductance transmembrane regulator diagnostic tests.