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We report two families, members of which are carriers of a novel hemoglobin (Hb) variant that was named Hb Olivet [α13(A11)Ala→Thr (α1) (GCC > ACC); HBA1: c.40G > A; p.Ala14Thr]. The analysis of these cases allowed a clear description of this anomaly that behaves as a silent Hb. In the first family, of Portuguese ethnicity living in France, the proband, a 24-year-old male and his 57-year-old mother, both appeared to be carriers. The son presented with borderline mean corpuscular volume (MCV), while the mother was normocytic and normochromic. Hemoglobin separation on capillary electrophoresis (CE) was normal, while a slightly asymmetric peak was observed on high performance liquid chromatography (HPLC). In a second family, originally from Surinam but living in The Netherlands, the proband, a 6-year-old girl, showed a mild microcytosis at low ferritin levels. The abnormal Hb was inherited from the mother who was clearly iron depleted, was not present in the sister and brother of the proband. The microcytic hypochromic anemia was only shown in two out of a total of four carriers. It therefore seems likely that iron depletion is causative as two carriers are completely normal. Characterization and genotype/phenotype correlation are briefly described.

We describe the characterization of a novel 7.9 kb deletion that eliminated one of the duplicated alpha-globin genes, causing an alpha+-thalassaemia phenotype in two independent carriers of Suriname-Indian origin. The molecular characterization of the deletion breakpoint fragment revealed neither involvement of Alu repeat sequences nor the presence of homologous regions prone to recombination, suggesting a non-homologous recombination event. This alpha+-thalassaemia deletion was found to give rise to an atypical haemoglobin H (HbH) disease characterized by a non-transfusion-dependent moderate microcytic hypochromic anaemia in combination with a poly adenylation signal mutation of the alpha-globin gene (alpha2 AATAAA --> AATA-- --).