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Key Points Elevation of HbF in 3 patients heterozygous for distinct 2p15-p16.1 syndrome microdeletions affecting BCL11A. Identification of novel, putative regulatory elements downstream of BCL11A that govern its expression in erythroid cells.

This study aims to report the willingness of different populations of high-risk couples to undergo preimplantation genetic diagnosis (PGD) for beta-thalassaemia as an alternative to prenatal genetic diagnosis (PND), and the willingness of infertile couples to undergo PGD for aneuploidies. An information sheet and questionnaire presenting PGD and PND procedures were distributed to four population types: 54 high-risk couples for beta-thalassaemia coming for their first PND (population A); 51 similar couples coming for their second or further PND without previous experience of therapeutic abortion (population B-na); 50 similar couples coming for their second or further PND with previous experience of therapeutic abortion for beta-thalassaemia-affected fetus (population B-ab); and 74 infertile couples undergoing routine in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) (population C). Favourable first impressions towards PGD compared with PND were observed in all four populations in the following proportions: 79.6% population A; 76.5% population B-na; 92.0% population B-ab; and 96.0% population C. Willingness to undergo PGD for beta-thalassaemia was as follows: 44.4% population A; 47.1% population B-na; and 72.0% population B-ab. We conclude that previous experience of PND for beta-thalassaemia is a crucial point in the willingness to accept the PGD procedure, and that couples belonging to population B-ab are the most suitable to undergo PGD for beta-thalassaemia. Some 96.0% of infertile couples in population C were ready to undergo PGD for aneuploidies.

We report a retrospective analysis carried out on 23,485 subjects submitted to a screening program from 2000 to 2006. Of these subjects, 3,934 had borderline HbA2 values from 3.1 to 3.9%; 410 samples, analyzed previously using PCR methods and sequencing because all of these were partners of a carrier of classical ␤-thalassemia, were selected for statistical analysis. Of 410 subjects, 94 (22.9%) were positive for a molecular defect in the ␤-, ␦-or ␣-globin genes. The most prevalent molecular defects were ␤ IVS1 nt 6 (HBB c.92+6T C), co-inheritance of severe ␤ thalassemia and ␦ mutations, ␤-promoter mutations and triplication of ␣ genes were detected; ␣-thalassemia and Hb-variants were also evident. Borderline HbA2 is not a rare event in a population with a high prevalence of ␤-thalassemia carriers. These data support the necessity to investigate these cases at a molecular level, particularly if the partner is a carrier of ␤-thalassemia.

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