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MUTATION | |
T->C at codon 131 of the alpha2 gene; TCT->CCT | |
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AMINO ACID REPLACEMENT | |
Ser->Pro replacement at position 131 (Hb Questembert) | |
TYPE OF ALPHA-THAL | |
alpha-Thal-2 [alpha(T)alpha/alphaalpha] | |
MECHANISM | |
Unstable Hb leads to a deficit in alpha chain production | |
IDENTIFICATION | |
Gene mapping; amplification of the alpha2-globin gene; sequencing | |
HEMATOLOGY IN HETEROZYGOTE(S) | |
Hb 10.0-10.3 g/dl; MCV 73-75 fl; MCH 24-26 pg; reticulocytes 115-300 x 109/l; alpha/beta ratio 0.80-0.82 | |
HEMATOLOGY IN HOMOZYGOTE(S) | |
Not observed | |
OCCURRENCE | |
In a French family of Yugoslavian descent (two carriers) | |
HAPLOTYPE | |
Not determined | |
FOUND IN COMBINATION WITH ABNORMAL HB(S) | |
Not reported | |
FOUND IN COMBINATION WITH BETA-THAL ALLELE(S) | |
Not reported | |
OTHER INFORMATION | |
Heat stability test was positive; the abnormal Hb was detectable by electrophoresis at pH 8.6; by chromatography; quantity ~11% | |