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| MUTATION | |
Codon 110 (T->C); CTG(Leu)->CCG(Pro) | |
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| AMINO ACID REPLACEMENT | |
Leu->Pro (Hb Showa-Yakushiji) | |
| TYPE OF BETA-THAL | |
beta+ | |
| MECHANISM | |
The T->C mutation results in the synthesis of an extremely unstable betaX chain which is rapidly catabolized by proteolysis | |
| IDENTIFICATION | |
Cloning; DNA sequencing; MspI digestion and Southern blotting because a recognition site is created by this mutation | |
| HEMATOLOGY IN HETEROZYGOTE(S) | |
| | Proband | Sister | Mother |
| Hb (g/dl) | 7.6 | 9.8 | 9.0 |
| MCV (fl) | 56.0 | 60.0 | 60.0 |
| MCH (pg) | 17.8 | 19.1 | 20.0 |
| Reticulocytes (%) | 2.4 | 4.1 | 2.1 |
| Bilirubin (mg/dl) | 0.46 | 0.72 | 0.50 |
| Hb F (%) | 1.3 | 2.0 | 2.0 |
| Hb A2 (%) | 5.2 | 5.3 | 5.3 |
| Heat denaturation test (50°C) (%) | (-) | (-) | (-) |
| Isopropanol test | (-) | (-) | (-) |
| Electrophoresis (starch, IEF) | None | None | None |
| beta/alpha chain synthesis ratio | 0.8 | 0.8 | 0.7 |
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| HEMATOLOGY IN HOMOZYGOTE(S) | |
Not reported | |
| OCCURRENCE | |
In a Japanese family (proband, mother, sister), in a second (unrelated) Japanese individual, and in some UAE families | |
| HAPLOTYPE | |
Not reported | |
| FOUND IN COMBINATION WITH ABNORMAL HB(S) | |
Not reported | |
| FOUND IN COMBINATION WITH BETA-THAL ALLELE(S) | |
Not reported | |
| OTHER INFORMATION | |
No abnormal peak was observed by reversed phase HPLC when the Hb from reticulocytes, incubated with isotopically labeled amino acids, was analyzed | |
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| REFERENCES |
| 1. | |
Kobayashi, Y., Fukumaki, Y., Komatsu, N., Ohba, Y., Miyaji, T., and Miura, Y.: Blood, 70:1688, 1987. | |
| 2. | |
Hattori, Y., Yamane, A., Yamashiro, Y., Matsuno, Y., Yamamoto, Ki., Yamamoto, Ku., Ohba, Y., and Miyaji, T.: Hemoglobin, 13:657, 1989. | |
| 3. | |
Ohba, Y., Hattori, Y., Harano, T., Harano, K., Fukumaki, Y., Ideguchi, H., Cho, H.I., and Park, S.S.: Hemoglobin, 21:191, 1997. | |