Improvement and Evaluation on Bisulfite Modification of DNA for DNA Methylation Detection / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To establish a rapid and convenient method of DNA modification by bisulfite sodium for the detection of DNA methylation.</p><p><b>METHODS</b>Through increasing the bisulfite sodium concentration and the temperature of treatment, cutting down the modification time, besides using glassmilk to adsorb the DNA in the purification and recovery, to improve the methods of DNA modification. Efficiency of cytosine converted to thymine in MAGE-A3 gene and DAP-K gene fragments were analyzed by bisulfite sequencing PCR in order to evaluate the DNA modification effect among the improved method, traditional method and kit method.</p><p><b>RESULTS</b>The operating time of test was shortened to about 3 hours by the improved method; conversion rate of unmethylated cytosine to thymine was over 99%; compared with the traditional method and kit method, there was no significant difference (χ(2) = 0.0564, P > 0.05); the improved method was only for the unmethylated cytosine conversion modification, and there was no significant difference in process of methylated cytosine converted to thymine comparing with the traditional method (χ(2) = 0.0149, P > 0.05).</p><p><b>CONCLUSION</b>The improved method has high efficiency of DNA modification and has no significant effect on excessive modification;meanwhile, it has many advantages such as time-saving and easy to operate etc.</p>

Dyskeratosis congenital: clinical features and genotype analysis in two Chinese patients / 中华血液学杂志

<p><b>OBJECTIVE</b>To analysis the clinic and genotype in two Chinese patients with Dyskeratosis congenita (DC).</p><p><b>METHODS</b>The two patients were characterized by mucocutaneous abnormalities (abnormal nails, lacey reticular pigmentation, and oral leukoplakia), bone marrow failure. They were diagnosed with DC. DC genes were amplified by polymerase chain reaction (PCR), including DKC1, TERT, TERC, TINF2, NOP10, NHP2, then DNA sequencing was performed for abnormal exons.</p><p><b>RESULTS</b>An abnormal peak was found in exon 6 of TINF2 gene of the two patients. DNA sequencing showed a 845G→A transition in TINF2 gene in the two patients.</p><p><b>CONCLUSION</b>We should think about DC if the young patients with mucocutaneous abnormalities and marrow failure. TINF2 c.845G→A(R282H) does exist in the two patients. It is reported in China for the first time.</p>