IthaID: 611

Names and Sequences

Functionality: Globin gene causative mutation Pathogenicity: Pathogenic / Likely Pathogenic
Common Name: CD 75 (-GAC) HGVS Name: HBA2:c.226_228del
Hb Name: Hb Watts Protein Info: α2 75(EF4) Asp->0

Context nucleotide sequence:

Also known as:

Comments: Initially detected in a Mexican-American heterozygous trait individual (F/37) without apparent haematological manifestations (13.7 g/dL Hb, 83.5 fL MCV, 2.3% HbA2, 0.5% HbF). Electrophoresis on cellulose acetate at pH 8.6, as well as IEF, revealed an abnormal Hb band with the same mobility as Hb S. The concentration of the variant was 9.8% as determined by HPLC. Unstable variant as detected by isopropanol stability testing after 20 minutes of incubation. Detected in a Spanish asymptomatic individual (F/58) together with an intronic insertion in HBD gene. Normal haematological indices (15.4 g/dL Hb, 90.3 fl MCV, 27.5 pg MCH, 1.7% HbA2, 0.6% HbF), as well as normal peripheral blood smear and ferric metabolism. Abnormal Hb was observed on capillary zone electrophoresis in Z6 and as a slower peak than HbA at a retention time of 4.19 min by cation-exchange HPLC. Co-inherited with an HBD intronic variant.

We follow the HGVS sequence variant nomenclature and IUPAC standards.

External Links


Hemoglobinopathy Group: Thalassaemia and Structural Haemoglobinopathy
Hemoglobinopathy Subgroup: α-thalassaemia, α-chain variant
Allele Phenotype:α⁺
Stability: Unstable
Oxygen Affinity: N/A
Associated Phenotypes: Haemolytic anaemia [HP:0001878]


Chromosome: 16
Locus: NG_000006.1
Locus Location: 34118
Size: 3 bp
Located at: α2
Specific Location: Exon 2

Other details

Type of Mutation: Point-Mutation(Deletion)
Effect on Gene/Protein Function: Insertion/Deletion of codons (Protein Structure)
Ethnic Origin: Mexican-American, Spanish
Molecular mechanism: N/A
Inheritance: Recessive
DNA Sequence Determined: Yes

In silico pathogenicity prediction

Sequence Viewer

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Publications / Origin

  1. Rahbar S, Lee C, Fáirbanks VF, McCormick DJ, Kubik K, Madden BJ, Nozari G, Hb Watts [alpha 74(EF3) or alpha 75(EF4)Asp-->0]: a shortened alpha chain variant due to the deletion of three nucleotides in exon 2 of the alpha 2-globin gene., Hemoglobin, 21(4), 321-30, 1997 PubMed
  2. González Borrachero ML, de la Fuente-Gonzalo F, González FA, Nieto JM, Villegas A, Ropero P, [Delta⁰-thalassemia by insertion of 27 base pairs in δ-globin gene with decreased hemoglobin A₂ levels]., Med Clin (Barc) , 144(7), 312-6, 2015 PubMed
Created on 2010-06-16 16:13:16, Last reviewed on 2023-08-04 13:18:17 (Show full history)

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