General information
Globin chain involved
Status
Heterozygous
Migration zones
Migration positions
209
Sickle Cell Disease: No
Thalassemic variant: No
Capillary Electrophoresis
Fractions
Value %
Hb A
93.2
Hb Ahvaz
4.6
Hb A2
2.2
Comments
The hyperinstability of the rare variant Hb Ahvaz leads to the appearance of a small peak in the Z(D) zone, just at the boundary of the Z(S) zone.
Mutation data
Heterozygous Hb Ahvaz
Mutation
HGVS Nomenclature
Alpha2 83(F4) Leu>Arg
HBA2:c.251T>G
Hematological parameters
Name
Result
RBC Count
Normal to high
Total Hemoglobin
Normal
MCV
Low
MCH
Low
Blood smear
No information
Other analysis
No information
Comments on hematology
Mild hypochromia
Clinical context
Clinical presentation
Mild hemolytic anemia
Clinical risk
This mutation appears to act as a typical alpha+-thalassemia mutation and would be predicted to result in Hb H disease if inherited alongside an alpha0-thalassemia deletion
Variant information
Stability
Hyperunstable
Oxygen affinity
Increased
Ethnicities in literature
Found in Middle-East populations: met in two unrelated families in Khuzestan Province, southern Iran, and in a 27-year-old British female of Iranian or Middle East origin during prenatal testing
Comments on variant information
Leucine to Arginine amino acid change seems to increase oxygen affinity, heme loss, and instability. Thus, altering the spatial arrangements of the contact points decrease the affinity of the α-globin chain for the β-globin chain.
Scientific Literature
Scientific references
Globin Chain involved
Status
The term "Double Heterozygous" refers to cases of heterozygosity on different globin chain types, while the term "Compound Heterozygous" refers to cases of heterozygosity on the same globin chain type.
For example, S/G-Pest is a Double Heterozygous case (beta and alpha-globin chains are mutated) and S/C is a Compound Heterozygous case (only beta-globin chains are mutated).
Migration zones
Migration positions
In some cases (homozygotes, combination of the variant with thalassemia, transfused patients, degraded samples or unstable variants), the variation in the migration position may be greater than +/- 1 point.
For profiles with thalassemia, only Hb A2 and Hb F peaks, if present, are listed with migration positions.
Sickle Cell Disease
Thalassemic variant
Capillary Electrophoresis
Variant information
Ethnicities are provided for informational purposes only and are based on scientific literature and conference posters.
A hemoglobin variant may therefore be present in populations of ethnic origins or countries not listed here.
Hematological Parameters