Next-generation sequencing (NGS) technology has revolutionized the modern medicine approach and is expected to infuse all medical fields. NGS platform is non-invasive and requires less sample volumes or even a single cell. The speed, high sensitivity, and low cost per sample make it more attractive platform compared to any others. Currently, it is employed in clinics on a large scale either by sequencing the whole genome or the exome of a patient requiring medical diagnosis. As a result, several thousands of sequencing tests have been carried on patients by major hospitals in the world. Interestingly, reports have stated more than 25% success rate of diagnosing genetic disorders.
A person’s whole genome study allows one to interpret and understand the genetic cause of a disease and/or patients suffering from disorders that are posing challenges to clinical treatments. Although, NGS is inadequately understood, it enables to detect all kinds of genomic variations comprising single nucleotide variants, point mutations, insertion-deletions, copy number variants, inversions, repeat expansions and translocations. The whole genome sequencing can disclose structural variations or mutations that remain unnoticed by other molecular diagnosis such as the exome and Sanger sequencing or microarray studies. Irrespective of various NGS platforms used, the identification of variants is readily achievable, but interpreting the variant in a single patient still remains as a major challenge to clinicians. The genomic information of patients collected around the globe and stored in a secured format will be extremely adored to expand our knowledge of disease susceptibility and variant pathogenicity. The global sharing of the genomic data will be vital to understand the genotype-phenotype correlations, health and among geographically and religiously separated human populations. In this regard, several developments have been underway to adopt potential tools to analyze the massive genomic data and to interpret the results.
However, one of the major issue faced is ambiguity about the interpretation of genomic variants in individuals, generally while a patient show no known family history or symptoms of a disease. The efforts on such considerations are increasing continuously in recent times. Apparently, there are legal and ethical issues associated to medical genomics. In general, risks are related to the protection or confidentiality of an individual data and the danger of identifying dissimilar genomic variants. Thus, protecting patients right on the genomic data is very vital to enable its practical use. In this regard, educating the patients, physicians, and public about the genome, DNA and its part in health and diseases have certainly benefited in exploring the multiple benefits of medical genomics. As a consequence, genome sequencing has grown rapidly in recent times with nearly 10,000–50,000 genomes sequenced every year. Globally, several programs on genome sequencing have been initiated. Some of them include the 100,000 Genomes Project (http://genomicsengland.co.uk), FarGen (http://www.fargen.fo/en), and the precision medicine initiatives (http://www.nih.gov/precisionmedicine/). Likewise, many individual medical research labs are also undertaking projects to interpret individual variations on a daily basis. These innovations will eventually lead to a better understanding on the disease pathogenesis and bridge a new era of genomic pathology and precision medicine. However, a rapid, precise, complete and inexpensive methods such as NGS are urgently required to comprehend the promises of precision medicine. This allows diagnosing rare diseases and hereditary forms of cancers, in addition to prenatal testing for a disease such as Down syndrome. Recently, the number of immune deficiencies and genetic disorders are increasing and their detection being not available or undetected due to genetic heterogeneities. However, the inclusiveness of non-invasive NGS can diagnose accurately in such cases.
Medical investigations have embraced the NGS technology in diagnosing and understanding the genetic aspects of different cancer types. Efforts on registering mutations in several cancer types are in progress. It is expected to lead to new approaches of rapidly screening numerous gene targets, the management of disease and implementing targeted therapies against diseases. In addition, the data allows to speed up drug therapies and discover novel drug targets. In modern medicine, the correct prescription of precise drug at the right quantity to a particular patient is a major challenge. Therefore, the recommended use of correct drugs against a disease can be possibly achieved by using NGS platforms and exploring pharmacogenetics. For instance, as a non-invasive screening of trisomies, NGS can be used to sequence the fetus genome to detect all variations for all identified recessive states. Importantly, interpreting these genomic information to predict diseases is much more difficult in a prenatal setting. Further, projecting the time of a disease onset or its severity is more complicated in a prenatal setting. For many disorders, including mental disabilities, researchers have lately learned that the disorder is often due to de novo mutations which may not be detected through preconception screening methods. Genomic biomarkers have been extensively examined from assessing risk for cardiovascular diseases, detecting foetal genetic diseases to predicting treatment response of chemotherapeutic agents for cancers. Even now, clinicians or medical practitioners are unclear on the correct implementation of prenatal genetic screening, but this technology is going to be real soon.
In future, it is imaginable that genome sequencing will be executed in advance before a patient visiting a clinician. This could assist the clinician and other medical professionals to explore the genomic data precisely and establish the diagnosis and precise treatments. Implementing genomics in medicine would benefit from creating common set-up, such as a catalog of variants detected across large numbers of sequenced individuals to date, evidentiary standards tailored to benefits and risks, common clinical decision support tools including point-of-care educational materials, an updatable database of actionable variants, and collaborative projects to pool resources and identify best practices. To accelerate the clinical utility of genomic approaches, medical experts and geneticists are much more needed than ever to work together to decode and interpret clinically pertinent genomic data, with a collective goal of improving the patient health care.