ABSTRACT
The review considers the epigenetic defects and their diagnostics in several hereditary disorders and tumors. Aberrant methylation of the promoter or regulatory region of a gene results in its functional inactivation, which is phenotypically similar to structural deletion. Screening tests were developed for Prader-Willi, Angelman, Wiedemann-Beckwith, and Martin-Bell syndromes and mental retardation FRAXE. The tests are based on allele methylation analysis by methylation-specific or methylation-sensitive PCR. Carcinogenesis-associated genes (RB1, CDKN2A, ARF14, HIC1, CDI, etc.) are often methylated in tumors. Tumors differ in methylation frequencies, allowing differential diagnostics. Aberrant methylation of tumor suppressor genes occurs in early carcinogenesis, and its detection may be employed in presymptomatic diagnostics of tumors.
Subject(s)
Genetic Diseases, Inborn/diagnosis , Genetic Diseases, Inborn/genetics , Neoplasms/diagnosis , Neoplasms/genetics , Genomic Imprinting , Humans , Trinucleotide RepeatsABSTRACT
A PCR-based survey of allelic polymorphism of three microsatellite markers, DXS998, DXS548, and FRAXAC1, mapped to chromosome region Xp27.3, and two microsatellite markers, DXS8091 and DXS1691 located on Xq28 was carried out using a series of DNA samples obtained from 98 unrelated individuals from Russia. The number of alleles detected on electrophregrams for each marker tested was 4, 6, 4, 5, and 3, respectively. The values of heterozygosity index for the markers examined were 0.65, 0.27, 0.38, 0.70, and 0.29, respectively. The observed distribution of the allelic frequencies for each microsatellite marker examined fitted Hardy--Weinberg expectations. The values of individualization potential determined for each marker were 0.24, 0.53, 0.43, 0.12, and 0.52, respectively. In the sample tested the genotype distribution with regard to above loci was determined. The perspectives of using the analyzed allelic polymorphisms for indirect DNA diagnostics of the monogenic diseases located in this chromosome region (X-linked mental retardations, FRAXA and FRAXE) as well as for human population genetics and personal identification is discussed.
Subject(s)
Alleles , Dinucleotide Repeats , Polymorphism, Genetic , RNA-Binding Proteins , Chromosomes, Human, X , Fragile X Mental Retardation Protein , Fragile X Syndrome/genetics , Genetic Markers , Heterozygote , Humans , Microsatellite Repeats , Nerve Tissue Proteins/genetics , Nuclear Proteins/genetics , Russia , Trans-Activators/geneticsABSTRACT
Analysis of the errors and faults in the treatment of the main diseases of veins of the vena cava inferior system showed that they can be explained to a great extent by the uncoordinated ideas of the anatomy of the lower limb venous channel. Our experience suggested the expediency of evaluating the condition of venous circulation from the standpoint of comprehensive consideration of the vascular channel structure. The suggested scheme of the structure of the venous channel with all the collaterals and the intravenous connections is systematized and logically completed. We employed it for analysis of some up-to-date problems of the diagnosis and treatment of the most frequently encountered diseases of the lower limb venous system. Knowledge of the general and individual characteristics of the structure of the venous channel opens up new opportunities for their use in surgery and at the same time protect against unreasoned and erroneous decisions.
