Sequencing in Clinical Laboratory Diagnostics

Sequencing is a common name for methods that allow the establishment of the linear order of components in a macromolecule. Specifically, it refers to nucleotide sequencing, which decodes the primary structure of linear DNA and RNA molecules. This process is used for the diagnosis of rare hereditary diseases, oncogenetics, personalized medicine and pharmacogenomics. It is also used for studying infectious pathogens and microbiomes. The absolute advantage of molecular approaches is demonstrated by the fact that DNA analysis directly studies genotypes and is the only way to study primary disorders (mutations), which are the root causes of disease, better than other diagnostic methods, which are limited to phenotypic aspects. This includes the genome sequence, which is not the cause of disease, but rather an understanding of how it functions. It includes which genes are responsible for vital cell activity, how gene regulation occurs, and which gene pathways are activated in response to stress. The problem was solved by the development of high-throughput massively parallel sequencing technologies such as NGS (next-generation sequencing). NGS reads millions of short DNA fragments, up to 600 nucleotides long, simultaneously. NGS has wide-ranging applications in clinical and laboratory diagnostics and has both advantages and disadvantages. NGS allows us to examine the entire genome, providing a more comprehensive and detailed genetic picture compared to traditional sequencing methods. It can sequence millions of DNA fragments at once, significantly reducing time required for genetic analysis. However, one of the main challenges is managing the vast amount of data produced. Integrating NGS into everyday clinical practice presents challenges, including regulatory obstacles, the need for standardised protocols, and the provision of necessary training for doctors to interpret results accurately. Understanding and interpreting the results of NGS is a complex task requiring specialised knowledge in genetics and bioinformatics. The primary outcome of the development of genome-wide and post-genome technologies has been a substantial expansion in the possibilities for investigating the genetic basis of a wide variety of human illnesses. In this respect, research into the mechanisms of hereditary predisposition to multi-factorial diseases and identification of specific genetic indicators is particularly pertinent today.