Hemoglobin variants occur when there are mutations in specific genes that code for the protein chains, known as globins, which make up the hemoglobin molecule. This leads to amino acid substitutions in the hemoglobin molecule that could affect the structure, properties, and/or the stability of the hemoglobin molecule.

Here we review the major classes of hemoglobin variants, emphasizing general concepts and illustrative examples. More than 1000 natural variants of hemoglobin are known. They have different structures and biochemical properties (e.g., oxygen affinity), and their physiological effects range from insignificant to severe.

2005年5月9日 · Search for information on the genomic sequence changes leading to hemoglobin variants and all types of thalassemia and hemoglobinopathies. Extensive information is recorded for each variant and mutation, including sequence alterations, biochemical and hematological effects, associated pathology, ethnic occurrence and references.

In this review, the following are discussed: (i) the methods used for characterization of haemoglobin disorders; (ii) the problems linked to diagnosis of thalassaemic trait; (iii) the strategy for detection of common Hb variants; and (iv) the difficulties in identification of rare variants.

2013年3月1日 · More than 1000 naturally occurring human hemoglobin variants with single amino acid substitutions throughout the molecule have been discovered, mainly through their clinical and/or laboratory manifestations. These variants alter hemoglobin structure and biochemical properties with physiological effects ranging from insignificant to severe.

Hb variants can be categorized into three groups: variants that cause hemolytic anemia, variants with altered O 2 transport capacity, and variants with thalassemia phenotypes. Variants that cause hemolytic anemia either have changes in their physical properties (solubility) or have decreased protein stability (instability).

Here we review the major classes of hemoglobin variants, emphasizing general concepts and illustrative examples. gene mutations affecting hemoglobin (Hb), the major blood oxygen (O2) carrier, are common, affecting an estimated 7% of the world’s population (Weatherall and Clegg 2001; Kohne 2011).

The common Hb variants, Hb S and Hb C, are responsible for the majority of sickle cell disorders. Beta thalassemias are typically caused by point mutations that disrupt regulatory elements of gene expression. The majority of alpha thalassemias are caused by large deletions of one or both alpha globin genes (HBA1 and HBA2).

Here, we report updates to >600 HbVar entries, inclusion of population-specific data for 28 populations and 27 ethnic groups for α-, and β-thalassemias and additional querying options in the HbVar query page.

2016年1月12日 · Hemoglobin variants with reduced oxygen affinity often go hand-in-hand with mild anemia due to a decreased erythropoietin response, and are characterized by an increased p50 value and decreased oxygen saturation. Many variants also exhibit minor instability and slightly elevated methemoglobin levels.