Here, we present cases of structural Hb variants and thalassaemias which present either alone or together and reduce the level of HbA 2 at varying degrees. Furthermore, we present a novel structural mutation in the δ globin gene, called Hb A 2 -Madrid.

Hemoglobin A2 (HbA2) is a normal variant of hemoglobin A that consists of two alpha and two delta chains (α 2 δ 2) and is found at low levels in normal human blood. Hemoglobin A2 may be increased in beta thalassemia or in people who are heterozygous for the beta thalassemia gene.

In 65 (38%)/172 subjects with phenotypic α (+)-thalassemia trait, the mean HbA2 (2.43 ± 0.24%) was 0.13% lower than in subjects without α (+)-thalassemia trait, P < 0.0001. The mean HbA2 did not differ between males and females, smokers and nonsmokers, and between the tribes.

To address low levels of HbA2 specifically, it's crucial first to identify the underlying issue through comprehensive blood tests and possibly genetic testing. Once the cause is identified, a healthcare provider can recommend a treatment plan.

Low Hb A2 percentages were found in iron-deficiency anemia, hereditary persistance of fetal hemoglobin, and Hb H disease. In iron-deficiency anemia, the lowest levels of Hb A2 were observed in association with the most severe anemia.

2013年3月12日 · Since iron deficiency and α+ -thalassemia are both common and both lower HbA 2, modifications in screening recommendations for BTT are proposed. 1. Introduction. Screening for β -thalassemia trait (BTT) depends on measuring hemoglobin (Hb) A 2 accurately.

Hemoglobin A2 (HbA2) is a normal variant of hemoglobin A that consists of two alpha and two delta chains (α 2 δ 2) and is found at low levels in normal human blood (1.5%–3.1% of all hemoglobin molecules in adults) and is increased in people with SCD (http://www.ncbi.nlm.nih.gov/books/NBK1377/).

A primary screening approach is recommended in countries with low frequency and limited heterogeneity of thalassaemia, while complete screening is recommended in populations where both α- and β-thalassaemias are common, and where interaction of α- and β-thalassaemias could lead to missed diagnoses due to the normalisation of red cell indices.

HbA 2 is usually raised in the beta thalassaemia (with a mild microcytic anaemia), and in unstable haemoglobinopathies where the amino acid substitution is on the beta chain.

Pitfall: Normal individuals with low MCH due to iron deficiency or a-thal trait, may have a HbA2 of 3.5-4% due to hyperthyroidism or drugs for HIV. Raised HbF, >0.8%