الفهرس 
THE NORMAL HEMOGLOBINOnly 14 pages are availabe for public view
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Abstract
-thalassemia is a heterogeneous disorder caused by mutations that reduce or abolish synthesis of -globin chain. It has been estimated that about 3% of the world population are heterozygous for -thalassemia and more than 300.000 children in the world are born with severe -globin gene disorder each year. The clinical severity of thalassemia major make it a priority genetic disease for prevention programs involving population screening of heterozygotes and optional prenatal diagnosis for carrier couples.
Real time PCR is a recently introduced method that integrates microvolume rapid-cycle PCR with fluorometry offering fluorescent characterization of PCR products for rapid genotyping without the need for post-PCR sample manipulation.
The current study was conducted on 37 -thalassemia carriers (including 5 AF samples). The commonest -thalassemia mutations in Egypt were characterized by real time PCR with fluorescently labeled hybridization probes specific for IVSI-110, IVSI-1, IVSI-6, codon 37 and codon 39 in 28/37 carriers. The commonest mutation encountered was IVSI-110 (46%), followed by IVSI-1 (16.2%) then IVSI-6 (13.5%). Codon 37 and codon 39 were not characterized in any sample. The genotype of the uncharacterized carriers was determined by a less sensitive method (reverse hybridization technique) and a relatively less common set of mutation were characterized as follows: IVSII-1(10.8%), codon 5 (5.4%), IVSII-745 (5.4%) and IVSI-116 (2.7%).
Impediments to prenatal diagnosis as encountered in our study were attributed to refusal of termination of pregnancy by the family on religious/cultural basis, abortion following amniocentesis and failure to determine the correct genotype of the analyzed AF.
In conclusion, the commonest mutations among Egyptians were found to be IVSI-110, IVSI-1, IVSI-6 and IVSII-1. The real time PCR method showed 100% reliability in detecting mutations assigned to its probes. It is specially suited for prenatal diagnosis as it is extremely rapid.