MUTATION | +1480 (C->G); also known as 3' terminating codon +6 (C->G) | ||||||||||||||||||||
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146 147 1 6 | |||||||||||||||||||||
AMINO ACID REPLACEMENT | None | ||||||||||||||||||||
TYPE OF BETA-THAL | beta+ (silent; only expressed in compound heterozygotes) | ||||||||||||||||||||
MECHANISM | Not clear; perhaps decreased stability of mRNA | ||||||||||||||||||||
IDENTIFICATION | Amplification of the beta-globin gene; DNA sequencing; dot-blot analysis with allele specific probes | ||||||||||||||||||||
HEMATOLOGY IN HETEROZYGOTE(S) | Four heterozygous relatives; beta/alpha in vitro chain ratio 0.8-0.84 | ||||||||||||||||||||
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HEMATOLOGY IN HOMOZYGOTE(S) | None | ||||||||||||||||||||
OCCURRENCE | In a Greek family | ||||||||||||||||||||
HAPLOTYPE | VI [- - + + - - - +] | ||||||||||||||||||||
FOUND IN COMBINATION WITH ABNORMAL HB(S) | None | ||||||||||||||||||||
FOUND IN COMBINATION WITH BETA-THAL ALLELE(S) | The 9-year-old proband is a compound heterozygote for this mutation and IVS-I-1 (G->A); Hb 7.7 g/dl; Hb A2 4.7%; Hb F 10.0%; rarely requires blood transfusions; mild thalassemic features | ||||||||||||||||||||
OTHER INFORMATION | None |
REFERENCES | |||
1. | Jankovic, L., Dimovski, A.J., Kollia, P., Karageorga, M., Loukopoulos, D., and Huisman, T.H.J.: Int. J. Hematol., 54:289, 1991. |