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Le diagnostic du deficit en α-1 antitrypsine (A1AT) repose sur la focalisation isoelectrique des proteines seriques et sur la mesure de la concentration serique. Cependant, la focalisation isoelectrique est techniquement delicate et une concentration fortement abaissee en A1AT sans bande anormale en focalisation isoelectrique ne permet pas de differencier un variant instable d’un variant dit « nul » (c’est-a-dire sans aucune expression phenotypique) a l’etat heterozygote. Dans la presente etude, nous avons compare les resultats du dosage, du phenotype et du genotype de l’A1AT chez 50 patients. Les alleles A1AT normaux (Pi*M1 a Pi*M4) ou deficitaires les plus courants (Pi*S et Pi*Z) ont ete parfaitement identifies au phenotypage. En revanche, le genotypage s’est avere necessaire pour caracteriser : (i) certains alleles A1AT plus rares (S-Munich, X-Christchurch) ; (ii) un allele nul et ; (iii) deux nouveaux alleles A1AT non encore decrits dans la litterature. En conclusion, meme si le genotypage A1AT n’est generalement pas necessaire, il est indispensable pour resoudre les cas complexes et pour obtenir des temoins valides pour la focalisation isoelectrique.

Background β-Globin haplotypes are important to predict the clinical development of patients suffering from sickle cell disease (SCD). Five main haplotypes (Benin, Bantu, Senegal, Cameroon and Arabic–Indian) are defined for βS chromosomes and their determination usually requires the genotyping by restriction fragment length polymorphism (RFLP) of six to eight single nucleotide polymorphisms (SNPs). However, RFLP is time-consuming and can lead to a misdiagnosis in case of a supplementary SNP on the restriction sequence. We propose a rapid β-globin haplotyping method using fluorescence resonance transfer (FRET) and high resolution melting (HRM) assays. Methods We have settled a fluorescence resonance energy transfer (FRET) assay for HincII e, XmnI, HindIII Gγ, HindIII Aγ, HincII δ and a high resolution melting (HRM) assay for HincII ψβ. These six SNPs are sufficient in most cases to determine the βS haplotype. Results Our methodology allowed us to successfully determine the β-globin haplotypes of 139 patients suffering from sickle cell disease. For some βS / β0-patients, a supplementary SNP has been identified on the HindIII Gγ restriction sequence leading to a false-negative RFLP result. Conclusion Combination of FRET and HRM assays is a rapid and reliable method for the β-globin gene cluster haplotyping.

We present here the case-report of a man with a severe G6PD deficiency revealed after the use of rasburicase (uricolytic drug) during a chemotherapy protocol. The genotypic analysis done to confirm the biochemical measurement revealed the 'Mediterranean mutation' at the hemizygous state (G6PD gene is located on chromosome X). Consequently to this diagnose, a search for G6PD deficiency has been performed (at the biochemical and genotypic levels) for the 9 children (7 daughters and 2 sons) of the proband. Surprisingly, one of his son was found to be hemizygous for the mediterranean mutation and one of his daughter appeared homozygous for this same mutation. This implies that the proband's wife (not studied) is certainly heterozygous for the mediterranean mutation, as it is very unlikely that this mutation had appeared de novo for two children of this couple.

We present here five new hemoglobin (Hb) variants which have been identified during routine Hb analysis before their genotypic characterization. Four of these result from a classical missense mutation: Hb Canuts [α85(F6)Asp→His (α1)], Hb Ambroise Pare [α117(GH5)Phe→Ile (α2)], Hb Beaujolais [β84(EF8)Thr→Asn] and HbA2-North Africa [δ59(E3)Lys→Met]. The last one, Hb Monplaisir [β147 (Tyr-Lys-Leu-Ala-Phe-Phe-Leu-Leu-Ser-Asn-Phe-Tyr-158-COOH)], results from a frameshift mutation at the stop codon of the β-globin gene which leads to a modified C-terminal sequence in the β-globin chain. None of these variants seem to have a particular clinical expression in the heterozygous state. The circumstances of the discovery of these five new Hb variants emphasize the fact that an association of techniques is necessary for a complete screening of Hb variants during routine Hb analysis. Globin chain separation by reversed phase liquid chromatography (RP‐LC) appears to be the most relevant method.

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We report here two new beta(0)-thalassemic mutations. In the first case, a deletion of two nucleotides (-CC) at codon 142 was found in a French Caucasian woman. In the second case, an insertion of a single nucleotide (+T) at codon 45 was found in a Turkish girl. In both cases, no dominant thalassemia-like phenotype was observed.

We have identified a deletion of 125 bp (α-α(Δ125)) (NG_000006.1: g.37040_37164del) in the α-globin gene cluster in a Kabyle population. A combination of singlex and multiplex polymerase chain reaction (PCR)-based assays have been used to identify the molecular defect. Sequencing of the abnormal PCR amplification product revealed a novel α1-globin promoter deletion. The endpoints of the deletion were characterized by sequencing the deletion junctions of the mutated allele. The observed deletion was located 378 bp upstream of the α1-globin gene transcription initiation site and leaves the α2 gene intact. In some patients, the α-α(Δ125) deletion was shown to segregate with Hb S (HBB: c.20A>T) and/or Hb C (HBB: c.19G>A) or a β-thalassemic allele. The α-α(Δ125) deletion has no discernible effect on red cell indices when inherited with no other abnormal globin genes. The family study demonstrated that the deletion is heritable. This is the only example of an intergenic α2-α1 non coding DNA deletion, leaving the α2-globin gene and the α1 coding part intact.

A new hemoglobin (Hb) variant in the heterozygous state, Hb Al-Hammadi Riyadh [codon 75 (GAC→GTC); α75(EF4)Asp→Val (α2)] corresponding to an A→T transversion on the second exon of the α2-globin gene, is described. The variant was characterized by DNA sequencing and mass spectrometry (MS). The variant was found during a routine Hb analysis for anemia in a 16-month-old boy who lived in Riyadh, Kingdom of Saudi Arabia.

A new mutation of the beta-globin gene initiation codon, ATG--AAG (Met--Tyr), is reported in a man originating from the southeast of France. Typical hematological findings of beta-thalassemia (thal) trait were found. We emphasize the importance of characterizing uncommon beta-thal mutations for genetic counseling.

Two new β‐globin chain variants: Hb Tripoli: codon 26, GAG→GCG [β26(B8)Glu→Ala] and Hb Tizi‐Ouzou: codon 29, GGC→AGC [β29(B11)Gly→Ser] are described on the first exon of the β‐globin gene. The two variants are characterized by DNA sequencing and mass spectrometry (MS). Hematological abnormalities were found in the two carriers. The presence of microcytosis and hypochromia is explained by an additional homozygous 3.7 kb α+ thalassemic deletion for the carrier of Hb Tizi‐Ouzou. Hb Tizi‐Ouzou showed a slight instability in vitro. The same hematological abnormalities associated with anemia are difficult to explain for Hb Tripoli's carrier in the absence of an α‐globin genes abnormality and could suggest a possible abnormal splicing.

We report a new mutation on the α2-globin gene causing α(+)-thalassemia (α(+)-thal) with a deletion of a single nucleotide (T) at amino acid residue 43 [HBA2:c.130delT or HBA2:c.131delT]. This frameshift deletion gives rise to a premature termination codon at codon 47.

We present two case reports in which an HBD mutation is present with a rare α hemoglobinopathy that substantially complicates the associated phenotype. In the first case, a new δ-globin variant, Hb A2-Pierre-Benite [δ83(EF7)Gly→Arg; HBD: c.250G>C] is associated with Hb Groene Hart [α119(H2)Pro→Ser (α1); HBA1: c.358C>T], an α-thalassemic variant. In the second case, a δ(+)-thalassemic variant, δ4(A1)Thr→Ile; HBD: c.14C>T, is associated with a newly described deletion of the hypersensitive site 40 (HS-40) region on the α-globin gene cluster. In both patients, a δ-globin mutation was suspected because of an abnormally low Hb A2 level, whereas the α hemoglobinopathy was sought to explain the slight microcytosis and hypochromia presented by the probands.

Hemoglobin Debrousse (beta 96[FG3]Leu-->Pro) is a new unstable variant, with high oxygen affinity responsible, in the steady state, for an apparently well-compensated chronic hemolytic anemia. The functional properties of this variant are due to the replacement of a leucine residue which is involved in the hydrophobic environment of the proximal side of the heme. This electrophoretically neutral hemoglobin was found as a de novo case in a 6-year-old girl suffering from severe anemia with hemolysis and transient aplastic crisis, following infection by parvovirus B19.

Background Deletions represent about 5% of the mutations in the β-globin gene cluster. We report here the screening for such deletions in the two French urban areas of Paris and Lyon between 2003 and 2010. Methods Semi-quantitative PCR methods were used for the first screening of deletions. Thereafter, a specific gap-PCR, eventually followed by DNA sequencing, was used for precise identification. Results 285 patients bore a deletion or recombination event in the β-globin gene cluster. Hbs Lepore or anti-Lepore were detected in 99 patients. Among the remaining 186 patients, 132 bore a deletion that could be fully identified. The most prevalent deletions were the Ghanaian HPFH-2 (n = 46), the Sicilian (δβ) 0 -thal (n = 22) and the Spanish (δβ) 0 -thal (n = 12). The other characterized deletions were the: HPFH-3, HPFH-1, Filipino, Senegalese, Corfu, Kabilian, − 1.39 kb, Indian − 619 bp and − 468 bp. Interestingly, three new deletions were fully characterized: a − 7719 bp deletion, a − 27,825 bp deletion with a 25 bp insertion and a − 125 bp deletion. Conclusions The present study emphasizes the importance to detect deletions in the β-globin gene cluster, particularly for at risk couples. The new − 27,825 bp deletion illustrates the complexity to understand the transcriptional regulation of fetal to adult hemoglobin switch.

Deletions in the β-globin locus control region (β-LCR) lead to (εγδβ)(0)-thalassemia [(εγδβ)(0)-thal]. In patients suffering from these rare deletions, a normal hemoglobin (Hb), phenotype is found, contrasting with a hematological thalassemic phenotype. Multiplex-ligation probe amplification (MLPA) is an efficient tool to detect β-LCR deletions combined with long-range polymerase chain reaction (PCR) and DNA sequencing to pinpoint deletion breakpoints. We present here a novel 11,155 bp β-LCR deletion found in a French Caucasian patient which removes DNase I hypersensitive site 2 (HS2) to HS4 of the β-LCR. Interestingly, a 197 bp insertion of two inverted sequences issued from the HS2-HS3 inter-region is present and suggests a complex rearrangement during replication. Carriers of this type of thalassemia can be misdiagnosed as an α-thal trait. Consequently, a complete α- and β-globin gene cluster analysis is required to prevent a potentially damaging misdiagnosis in genetic counselling.

Despite the fact that mutations in the human beta-globin gene cluster are essentially point mutations, a significant number of large deletions have also been described. We present here four new large deletions in the beta-globin gene cluster that have been identified on patients displaying an atypical hemoglobin phenotype (high HbF) at routine analysis. The first deletion, which spreads over 2.0 kb, removes the entire beta-globin gene, including its promoter, and is associated with a typical beta-thal minor phenotype. The three other deletions are larger (19.7 to 23.9 kb) and remove both the delta and beta-globin genes. Phenotypically, they look like an HPFH-deletion as they are associated with normal hematological parameters. The precise localization of their 5' and 3' breakpoints gives new insights about the differences between HPFH and (deltabeta)(0)-thalassemia at the molecular level. The importance of detection of these deletions in prenatal diagnosis and newborn screening of hemoglobinopathies is also discussed.

Subjects heterozygous for point mutations or short deletions at the polyadenylation (poly A) site of the β‐globin gene have mild β+‐thalassemia (thal) [[1]]. Several β+‐thal point mutations have be...

Many large deletions removing the entire α-globin gene cluster on the short arm of the human chromosome 16 (16p13.3) have been described.[1][1]–[3][2] At the heterozygous state, the resulting phenotype consists in α-thalassemia (α-thal) for relatively short deletions (100 to 356 kb) while an