A C----T substitution at nt--101 in a conserved DNA sequence of the promotor region of the beta-globin gene is associated with “silent” beta-thalassemia

摘要: Sequence analyses and dot-blot with synthetic oligonucleotide probes have identified eight individuals in three Turkish families one Bulgarian family chromosome having a C\---|-T mutation at nucleotide position--101 relative to the Cap site of beta-globin gene. This is part conserved blocks nucleotides within promoter region; vitro expression chloramphenicol acetyltransferase system showed that this substitution will decrease effectiveness transcription. Five subjects had thalassemia intermedia due additional presence known classical high hemoglobin (Hb) A2 beta-thalassemia on second chromosome; their hematologic condition was relatively mild. The persons heterozygosity for the--101 normal data without microcytosis but high-normal levels Hb mild imbalance chain synthesis. newly discovered considered silent types beta- thalassemia. It rare because it absent among several hundred chromosomes.