Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied 111 cases of Hb H disease from different families using Bam HI and Bgl II restriction enzymes. The results showed that 76 cases (68.5%) were of the deletion type, eight cases (7.2%) had Hb Constant Spring (Hb CS), and 27 cases (24.3%) were of the nondeletion and Hb CS types (alpha T). Distribution of the alpha-thalassemia-2 (alpha-thal-2) gene varies with the different regions in China. The rightward deletion (alpha -3.7) is found chiefly in Guangdong Province, the leftward deletion (alpha -4.2) mostly in Jiangxi Province, and the nondeletional type in Guangxi Province where the Han nationality is most prominent. We studied the nondeletional Hb H type by DNA gene mapping, digestion with Msp I, and hybridization with a 32P-alpha probe for the presence of the Hb Quong Sze [alpha 125(H8)Leu----Pro] mutation. It appears that none of these alpha-thal-2 genes contain the Hb Quong Sze mutation.
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PMID:The types and distribution of alpha-thalassemia-2 in China. 320 88

Recent studies show that the region of DNA brought into close proximity to the fetal gamma-globin genes in deletional forms of hereditary persistence of fetal hemoglobin (HPFH) is selectively hypomethylated (and presumably active) in normal erythroid tissue. This region is normally located approximately 100 kilobases (kb) 3' to the fetal genes. The continued expression of fetal hemoglobin in adult life in these forms of HPFH has been ascribed to the effect of this erythroid-specific region in altering local chromosomal structure and allowing transcription. Because transcriptional activity is often associated with hypomethylation, we have examined the methylation status of the gamma-globin genes and the truncated psi beta gene on the HPFH chromosome to determine whether juxtaposition of this erythroid-specific region results in a generalized hypomethylation of the globin gene region upstream of the deletion breakpoint. Genomic DNA purified from nucleated red blood cells (nRBC) from a patient with HPFH-2/beta O thalassemia was digested with Msp I or Hpa II, and the methylation pattern determined on the HPFH chromosome by using secondary cleavage with restriction enzymes which span the deletion breakpoint. These studies show that in nRBC the HPFH-2 chromosome is hypomethylated in the 3'-juxtaposed region (3'JR) and in the region of the gamma-globin genes. In contrast, Msp I sites near the truncated psi beta-globin gene remain methylated, suggesting that only a subset of CpG sites upstream from the 3'JR become hypomethylated in HPFH-2. This subset of sites corresponds to those which are normally hypomethylated when fetal genes are active. The continued high level of fetal globin expression is, therefore, not associated with a generalized hypomethylation upstream from the deletion junction.
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PMID:DNA methylation in hereditary persistence of fetal hemoglobin (HPFH-2). 360 70