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MUTATION | |
Codons 31/32 (+CGG) | |
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30 31 32 30 31 32 AG^G·CTG·CTG->AG^G·CGG·CTG·CTG | |
AMINO ACID REPLACEMENT | |
+Arg between positions 30/31: | |
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30 31 32 ARG·ARG·Leu-Leu | |
TYPE OF BETA-THAL | |
beta° (dominant beta°-thal) | |
MECHANISM | |
The abnormal mRNA translates into an abnormal beta chain which is 147 amino acids long and is unstable; an abnormal Hb was not recovered | |
IDENTIFICATION | |
Amplification of the beta-globin gene; DNA sequencing; dot-blot analysis with allele specific probes; ASO | |
HEMATOLOGY IN HETEROZYGOTE(S) | |
Proband: Hb 9.9 g/dl; MCV 79.8 fl; MCH 23.5 pg; reticulocytes 9.9%; Hb A2 4.9%; Hb F 1.9%; splenomegaly (two carriers are splenectomized); dark-colored urine; icteric | |
HEMATOLOGY IN HOMOZYGOTE(S) | |
Not observed | |
OCCURRENCE | |
Found in a Spanish family (four members) | |
HAPLOTYPE | |
Not done | |
FOUND IN COMBINATION WITH ABNORMAL HB(S) | |
Not reported | |
FOUND IN COMBINATION WITH BETA-THAL ALLELE(S) | |
Not reported | |
OTHER INFORMATION | |
The three base pair insertion was confirmed by electrophoretic examination of cDNA fragments | |