Genetics in the Third Millennium
Volume:5 Issue: 3, 2008

Thalassemia is one of the most common hemoglobin disorders, in which alpha-thalassemia appears in affected individuals with hypochromic microcytic anemia. Because of the absence of the mutation detection capabilities in the most health care centers in Iran, the most patients with alpha-thalassemia misdiagnosed as β silent carriers. Until now, no inclusive research has been done to expose the patterns of it in Khuzestan. Therefore, in the present study we decided to clarify the prevalence of the mutations in α-Thalassemia in Khuzestan. One hundred and fourteen patients from Khuzestan were selected among the patients, referred to Kariminejad & Najmabadi Pathology and Genetics Center, between 1998-2006, showing the signs of hypochromic microcytic anemia and normal HbA2 levels. First of all, they were all tested for 3 common α-thalassemia mutations,-3.7, -4.2, --MED, by gap-PCR amplification method. Alpha-Globin Strip Assay of the nine mutation panel and DNA sequencing was used to determine other major contributes in Khuzestan. We could detect α-thalassemia mutations for 84.2% of tested individuals. 79.2% had cis-type α-thalassemia, 13.5% trans-type and 7.3% was a carrier for two cis-type mutations. In total, 72.9% were silent carrier, 19.8% α-thalassemia trait, and 7.3% had α-thalassemia major. As an early report 27.4% of the tested alleles were found to be mutated. The –α3.7 single gene deletion was the most frequent α-globin mutation in our population representing 55.2% of α-thalassemia mutations in Khuzestan. Twelve other mutations (--MED, αPA2(GAA), - α4.2, αcd19, α-5nt, acd14, αPA1(AAG), αCS, anti 3.7triplication. We strongly recommend screening for the identified ten common mutations to improve the molecular diagnosis of anemia. =

Retinoic acid (RA) is a vitamin A derivative that exerts profound influences in vertebrate development and physiology. All-trans RA and 9-cis RA, are important regulators of embryonic development, cellular activity and tissue homeostasis. Their biological effects are mediated by two families of nuclear hormone receptors, retinoic acid (RAR) and retinoid X (RXR) receptors, which are ligand-dependent transcription factor. In the form of RAR-RXR or RXR-RXR dimers, the receptors act through binding to retinoic acid response elements (RAREs) present in the transcription regulatory region (promoter) of target genes. The identification of the pattern of expression of each isoform is crucial to our complete understanding of retinoid physiology. Compound null mutations of retinoic acid receptor (RAR) genes lead to lethality in uterus or shortly after birth and to numerous developmental abnormalities. The role of RXRs in the mediation of the developmental retinoid signal is less clear, because RXRβ and RXRγ null mutant mice are viable and do not display any abnormality obviously related to a known function of vitamin A. Effects of retinoids in normal as well as abnormal development may be mediated by two members of retinoid receptors together, RARs and RXRs.