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MUTATION | |
Codons 123/124/125 (-ACCCCACC); ACC·CCA·CCA(Thr·Pro·Pro)->--- --- --A | |
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AMINO ACID REPLACEMENT | |
Shortened betaX chain (beta-Khon Kaen) | |
TYPE OF BETA-THAL | |
Dominant inclusion body beta-thal trait | |
MECHANISM | |
This deletion changes the reading frame and results in the synthesis of a betaX chain of 135 amino acids; the new codon 136 is a stop codon (TAA); the chain is likely rapidly catabolized creating this TYPE OF BETA-THAL | |
IDENTIFICATION | |
Amplification of the beta-globin gene and cloning; DNA sequencing; HphI digestion | |
HEMATOLOGY IN HETEROZYGOTE(S) | |
Not reported | |
HEMATOLOGY IN HOMOZYGOTE(S) | |
Not observed | |
OCCURRENCE | |
In a Thai patient with Hb E-beta-thal | |
HAPLOTYPE | |
Not determined | |
FOUND IN COMBINATION WITH ABNORMAL HB(S) | |
The proband is a 3-year-old boy with Hb E-beta-thal; he has severe disease: hepatosplenomegaly; Hb 2.7 g/dl; after splenectomy: Hb 8.2 g/dl; MCV 73.1 fl; MCH 25.6 pg; large inclusion bodies in blood upon incubation with dye | |
FOUND IN COMBINATION WITH BETA-THAL ALLELE(S) | |
Not observed | |
OTHER INFORMATION | |
Hb electrophoresis: Hb E (+A2) 40.0%; Hb F 60.0%; stability tests negative; the variant chain could not be detected by chromatographic procedures | |