We
know diseases capable of alter gene functionality, so they are changing
people's good quality of life. Among all genetic diseases, many of them could
be very rare in frequency inside human population, some anomalies are present on
less than 200,000 persons in United States or 1 from 2,000 in Europe. Although
low frequent health problems seem to be unusual, they affect millions and
millions of people over all continents and countries. Thus, because of its
frequency and difficult diagnosis, health care of a great number of people is
insecure. However, genetic technologies and the knowledge on gene functions
were rising and rising in our days, so this advances are going to be integrated
to health and genetic disorders detection.
Before
inquiring about diseases it is important to notice modern technology in genetic
analysis. All organisms are composed by DNA as genetic material, at the same
time, DNA is composed by four components: Adenine (A), Thymine (T), Guanine
(G), and Cytosine (C), so gene expression depends in a strong way on the
combination of this four components. In order to understand DNA and reveal ATCG
combinations, sequencing technique was developed, but it presents some
limitations, the longer DNA is, the less accuracy on ATCG detection. In our
days, sequencing accuracy is increasing due to the implementation of Next
Generation Sequencing (NGS) technology. NGS avoids sequencing limitations
analyzing millions and millions of short DNA fragments; this tool is universal
for every biological entity, and its capacities are starting to be applied to
human health.
With
NGS came two new analysis: whole genome sequencing (WGS) and whole exome
sequencing (WES). Both are powerful tools to detect genetic differences among
people. WES is the most popular to detect different proteins in human body
because it analyses only genes that becomes proteins in human body. However,
the two techniques allowed scientists to detect genes such as those which are
related to Freeman-Sheldon syndrome, Miller syndrome, and Schinzel-Giedion
syndrome. In addition, there are projects that are implementing and improving
different ways to discover more and more genes such as 1000 Genomes Project,
Exome Variant Server, or HapMap Project.
Moreover,
NGS based gene discovery revealed a lot of different sequences related to rare
diseases, but the depth this problems is
still unclear. Nowadays, it is common to find rare diseases with relationship
with others or discover new unrelated disorders. Anyway, NGS is a powerful
diagnosis tool since it started to be applied in the study of inherit mutations
or the frequency of a gene associated to a disease in a family. Finally,
researchers are more excited with the applications of NGS technologies in
public health since all the studies are deriving in the analysis of proteins or
seeking for new ways in the development of diseases.
In
conclusion, patients of rare genetic diseases are the most benefit with NGS
revolution. From this point, the discovery of genetic variations among people
will allow us to personalize medicine for each individual or each particular case.
Furthermore, with the existence of The Human Variome Project, a database with
all the genetic variations related to illnesses and health development, it is
necessary an Human Phenome Project focused on create a database with the
effects of this genetic variants on the human condition and healthy life.
References
Boycott,
K. M., Vanstone, M. R., Bulman, D. E., & MacKenzie, A. E. (2013).
Rare-disease genetics in the era of next-generation sequencing: discovery to
translation. Nature Reviews Genetics, 14(10), 681-691.
Illumina.
An introduction to Next-Generation Sequencing technology. Retrieved from: www.illumina.com/technology/sequencing_technology.ilmn
on 16/02/2015.
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