Hb Alessandria [ß37(C3)Trp→Leu; HBB: c.113G>T]: a Novel Variant on the ß-Globin Chain with Slightly Increased Affinity for Oxygen Detected by Capillary Electrophoresis.

We report a novel mutation on the ß-globin gene in a 68-year-old woman of Sicilian origin living in Alessandria, Italy. This mutation produces a hemoglobin (Hb) variant of Hb A that was detected by the capillary electrophoresis (CE) method during measurement of Hb A1c. The variant Hb did not separate from Hb A using different high performance liquid chromatography (HPLC) instruments. Direct DNA sequencing revealed a G>T transversion at codon 37 and subsequent substitution of a tryptophan residue for a leucine residue. The new Hb variant was named Hb Alessandria [ß37(C3)Trp→Leu; HBB: c.113G>T]. The p50 value was slightly decreased while the stability test at 37 °C in isopropyl alcohol and the main erythrocyte parameters were normal. Overall, the patient appeared clinically normal.

Two co-inherited hemoglobin variants revealed by capillary electrophoresis during quantification of glycated hemoglobin.

OBJECTIVES: The observation of numerous new structural defects in hemoglobin (Hb) has often been linked to the evolution and development of device technologies used for the separation and quantification of hemoglobin components. However, the increased use of preventive tests for hemoglobinopathies and separative methods to quantify glycated hemoglobin (HbA1c) also contributed to these observations, as demonstrated by the case described here. Our aim is to emphasize that different separative method can provide more useful information in patient management. METHODS: A 64-year-old diabetic woman of Moroccan descent was examined in the context of HbA1c monitoring. The test was performed using high performance liquid chromatography (HPLC) and capillary electrophoresis (CE) systems. Molecular characterization was performed by direct sequencing of the ß and α globin genes. RESULTS: The two methods used showed the presence of an anomalous fraction identified as HbS, already observed previously, but only through CE it was possible to observe the presence of another variant and its hybrid components. Direct sequencing of ß and α globin genes confirmed heterozygous HbS [ß6 (A3) Glu→Val; HBB: c.20A>T] and allowed to identify a mutation on the α2, [α114 (GH2) Pro→Leu gene; HBA2: c.344C>T] corresponding to the rare Hb Nouakchott variant. CONCLUSIONS: The two Hb variants highlighted by the EC and the molecular characterization therefore allowed adequate advice, the correct assessment of HbA1c and metabolic status and therefore better clinical management of the patient. The availability of different instruments in the same laboratory, confirming situations of diagnostic uncertainty, represents a valuable opportunity that should be encouraged.

Hemoglobin A2 and Heterogeneous Diagnostic Relevance Observed in Eight New Variants of the Delta Globin Gene.

BACKGROUND: Hemoglobin A (Hb A) (α2ß2) in the normal adult subject constitutes 96-98% of hemoglobin, and Hb F is normally less than 1%, while for hemoglobin A2 (Hb A2) (α2δ2), the normal reference values are between 2.0 and 3.3%. It is important to evaluate the presence of possible delta gene mutations in a population at high risk for globin gene defects in order to correctly diagnose the ß-thalassemia carrier. METHODS: The most used methods for the quantification of Hb A2 are based on automated high performance liquid chromatography (HPLC) or capillary electrophoresis (CE). In particular Hb analyses were performed by HPLC on three dedicated devices. DNA analyses were performed according to local standard protocols. RESULTS: Here, we described eight new δ-globin gene variants discovered and characterized in some laboratories in Northern Italy in recent years. These new variants were added to the many already known Hb A2 variants that were found with an estimated frequency of about 1-2% during the screening tests in our laboratories. CONCLUSIONS: The knowledge recognition of the delta variant on Hb analysis and accurate molecular characterization is crucial to provide an accurate definitive thalassemia diagnosis, particularly in young subjects who would like to ask for a prenatal diagnosis or preimplantation genetic diagnosis.

Hemoglobin Yamagata [ß132(H10)Lys→Asn; (HBB: c.399A>T)]: a mosaic to be put together.

OBJECTIVES: Artifactually altered glycated hemoglobin (HbA1c) concentrations are frequently linked to hemoglobin (Hb) variants. Their expression and detection require in-depth analysis. METHODS: Cation exchange high performance liquid chromatography (HPLC) (Bio-Rad Variant™ II; Trinity Biotech Premier Hb9210 Resolution), capillary electrophoresis (CE) (Sebia Capillarys 2 Flex Piercing) and mass spectrometry (MS) (Waters) were used for variant detection; Sanger sequencing, multiplex ligation-dependent probe amplification (MLPA) and next generation sequencing (NGS) were used for DNA analysis; HbA1c was measured with cation exchange HPLC (Bio-Rad Variant™ II; Arkray Adams HA-8180V; Tosoh HLC-723 G7), CE (Sebia Capillarys 2 Flex Piercing), boronate affinity HPLC (Trinity Biotech Hb9210 Premier), immunoassay (Cobas c501 Tina-quant HbA1c Gen. 3; Nihon Kohden CHM-4100 Celltac chemi HbA1c HA-411V) and enzymatic assay (Abbott Architect c 8000 HbA1c). RESULTS: Hb Yamagata [ß132(H10)Lys→Asn; (HBB: c.399A>T)] was identified in the proband by MS after the observation of an abnormal peak in HPLC and CE. A mosaic expression of this variant was detected by NGS (mutant: 8%; wild type: 92%), after negative results in Sanger sequencing. Hb Yamagata interfered with HbA1c measurements by cation exchange HPLC and CE whereas immuno and enzymatic assay values showed good agreement with boronate affinity HPLC measurement. CONCLUSIONS: A mosaicism of Hb Yamagata was found in a patient with altered HbA1c values. This rare gene variant was detected only by advanced technologies as MS and NGS. The variant interfered with common HbA1c determination methods.

Synthesis of new tren-based tris-macrocycles. Anion cluster assembling inside the cavity generated by a bowl-shaped receptor.

The synthesis of three new tris-macrocycles, containing three [12]aneN(4) (L1), [12]aneN(3)O (L2), or [14]aneN(4) (L3) moieties appended to a tren unit, is reported. The crystal structure of the [(Na(ClO(4))(6)) subset L1(2)H(13)]Na(6)Cl(2)(ClO(4))(12) compound shows the anionic cluster [Na(ClO(4))(6)](5)(-) assembled inside the cavity defined by two bowl-shaped polyammonium receptors, held by multiple charge-charge and hydrogen bond interactions.