| MUTATION | TAA->AAA at codon 142 of the alpha2 gene | ||
|---|---|---|---|
| AMINO ACID REPLACEMENT | Stop codon->Lys + 30 additional amino acids (Hb Icaria) | ||
| TYPE OF ALPHA-THAL | alpha-Thal-2 [alpha(T)alpha/alphaalpha] | ||
| MECHANISM | The T->A mutation results in extension of the alpha chain at the C-terminus with 31 amino acid residues; a stop codon is found at the new codon 173 | ||
| IDENTIFICATION | By protein analysis; amplification of the alpha2-globin gene and sequencing; dot-blot analysis with allele specific probes; ASO | ||
| HEMATOLOGY IN HETEROZYGOTE(S) | Hb 11.5-12.5 g/dl; MCV 78-86 fl; MCH 25-28 pg; Hb A2 2.3-2.7% | ||
| HEMATOLOGY IN HOMOZYGOTE(S) | No data available | ||
| OCCURRENCE | In the populations of Greece and the Balkan countries | ||
| HAPLOTYPE | Not determined | ||
| FOUND IN COMBINATION WITH ABNORMAL HB(S) | Not reported | ||
| FOUND IN COMBINATION | With various alpha-thal-2 and alpha-thal-1 alleles resulting in Hb H disease (see Refs. 3 and 4) | ||
| OTHER INFORMATION | Hb Icaria is present for <0.5% in heterozygotes; the variant is unstable |
| REFERENCES | |||
| 1. | Clegg, J.B., Weatehrall, D.J., Contopolou-Griva, I., Caroutsos, K., Poungouras, P., and Tsevrenis, H.: Nature, 251:245, 1974. | ||
| 2. | Efremov, G.D., Josifovska, O., Nikolov, N., Codrington, J.F., Oner, C., Gonzalez-Redondo, J.M., and Huisman, T.H.J.: Br. J. Haematol., 75:250, 1990. | ||
| 3. | Traeger-Synodinos, J., Kanavakis, E., Tzetis, M., Kattamis, A., and Kattamis, C.: Am. J. Hematol., 44: 162, 1993. | ||
| 4. | Kanavakis, E., Traeger-Synodinos, J., Papasotiriou, I., Vrettou, C., Metaxotou-Mavromati, A., Stamoulakatou, A., Lagona, E., and Kattamis, C.: Br. J. Haematol., 92:332, 1996. | ||