Molecular Advances to the Diagnosis of a Genetic Disorder

This essay evaluates the advances in the genetic mechanism and discusses the diagnosis of genetic disorders, focusing on Huntington's disease.

Running Head: GENETIC DISORDER
Molecular Advances to the Diagnosis of a Genetic Disorder

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Introduction
As per the research of Gopal et al. (2017), all the diseases have a genetic component
in them. However, the extent to which this genetic component influence the disease varies.
The essay aims to evaluate the advances in the genetic mechanism by evaluating the structure
of genetic materials and their alteration due to natural and artificial means. Furthermore, the
essay also focuses on the modes of inheritance for genetic disorder and discusses current
applications and impact of cell biology, genetics and biochemistry in terms of diagnosis of
genetic disorders. For the essay, autosomal dominant inheritance mode is selected. The essay
focuses on Huntington’s disease to evaluate the applications in diagnosing this genetic
disorder.
Structure of Genetic Material
The structure of DNA is comprised of two nucleic strands that are joined by hydrogen
bonding. According to Han et al. (2017), DNA combines itself in a double helix shape
containing hydrogen bonding between the bases of strands that shaped like rungs of a ladder.
Due to this structure, DNA is able to coil itself in a long chain molecule that is compact and
has the capacity to store lots of information. Wei et al. (2017) defined the complementary
base pairing that suggests that a larger purine always combines with the smaller pyrimidine,
thereby enables it to maintain a constant distance with its two DNA block bones through
which parallel polynucleotide chains are formed. This ensures that the two strands are
opposite to each other with the bases that allow DNA to holds coded information for protein
synthesis and enable accurate DNA replication. The double helix structure ensures that the
DNA could be unzipped for proper replication.

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DNA is the genetic material which is actually found into living organism. DNA, or
deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms.As
the DNA is almost to be found humans as all the cells of body. They are helpful in providing
the proper level of instructions regards to their respective growth, function and respond to
their respective environment. DNA is the long strings which is parried in chemical unit
differentiated into four level of types abbreviated as the A, T, C, G. This is helpful in card-
carrying all level of information in an organized manner into the units called as cells. The
four chemicals are named as the adenine, guanine, cytosine and thymine respective. The
consistency of human DNA is about the 3 million bases and more than 99% have the those
bases are considered to same in all properly.
The DNA have the pairing ups of different combination of A, T, C, G to have proper
formation of units as each unit is being attached to sugar and phosphatase molecules.
Nucleotides are arranged in two long strands that form a spiral called a double helix. The
structure of the former one same how about the double helix with bases pair forming the
ladder rungs and latter is having proper formations of vertical side pieces of the ladder,
The important property of DNA is that it can easily replicate and make respective
copies of themselves. The each stand of DNA have the formation of double helix which is
serving to be a pattern of more order duplication the sequence of base. This is considered to
be critical as the each new cell have formation of new patterns which is all about the copy
DNA present in old cell.
The DNA have the bioecological functions in which DNA polymer have direct level
of productiveness of other respective polymer which is call protein. All respective traits are
drive for the interactions of protein with each in surrounding environment. The next is about
the chromosome have the consistence of smaller segment as which is called as genes.

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The next function of DNA is that each gene is to further divided on to there
nucleotide sub segment which is called as codon. The codons of the DNA language are each
associated with specific amino acids.
Alteration of Genetic Material by Natural and Artificial Means
Various diseases are being caused by mutations which are basically inherited by
parents, can also been seen by individual during the time of birth. Some of the disease that
can be seen in child during when they are born is sickle cell disease. Other problems that are
being caused by acquired mutations in gene or group of genes can occur any time in person’s
life. Genetic disorders are basically caused by a mutation in only one gene cell. Mutation in
multiple genes are been caused by monogenic disorder. Multifactorial inheritance disorder is
been caused by combining mutation of genes and also taking in consideration the
environmental factors or by doing damage to chromosomes. Genetic disorder is been caused
by modifying the strucrural aspects of entirer chromosomes. These structuresd also carry
genes. It has also been analysed that all diseases which are been caused consists of genetic
components. Some of the diseases are been known as mutation that are basically inherited
and taken from parents (McColgan and Tabrizi, 2018). These disease are seen at the time of
child. There are also other type of mutations which are not being inherited from parents but
they occur because of some environmemtal factors or they can also occur randomly. If the
patient is engaged in smoking ciggerate then they can face problem of mutation. Many type
of cancers are also included in this and also forms of neurofibromatosis. There are various
types of genetic disease that is been caused because of change or abonromality in genes.
Some of the individuals faces this problem because they have inherited this from their
parents. Single gene gentic mutation is known as monogentic inheritance. There are various
single gene disorder. Some of the examples that can be taken as single gene disorder includes

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hutingtan’s disease. It is a type of genetic disorder which causes nerve cells to break down
laying negative impact on helath outcome of service users. In this type of genetic disorder a
person ability to think and act generally reduces their prime working hours. Early signs and
symptoms of this disease includes hopelessness, depression. Low mood is also a signs of
hutingtan’s disease. It is generally inherited by parents into child.
The most obvious method of genetic modification that dates back to nomadic history
and is still valid today is the process of natural or simple selection. In this method, the species
that tend to modify their behaviour or delivered certain traits according to the ecological need
continued the propagation. The traits modify naturally adjusting themselves by enhancing
their compatibility with nature. However, as the research of Scott and Wilkinson (2017)
describes crossing or interspecies crossing as the most significant method that naturally
contributes to gene modification. Crossing occurs when plants from one species transfer its
pollen to other plant producing a hybrid that contains the gene architecture of both parent
plants. However, the interspecies crossing has been developed significantly by the
development of the chromosome. Now plant breeders only exchange the dedicated gene to
include the desired effect in other plants. With the modern chromosome engineering
development, plant breeders can improve certain crop species like corn, soybean and barley
to improve the quality of crops (Scott and Wilkinson, 2017). Genetic engineering is the most
important and developed method for making alterations in the genetic material. Now,
scientists can include the targeted change in either animals or plants to achieve specific
results using rDNA technology. Few of the methods utilised in genetic engineering include
microprojectile bombardment, electroporation, microinjection and transposons (Ibiyemi,
2016).

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Mode of Inheritance Related to Huntington’s disease
Huntington’s disease is caused by the mutations in the HD gene which is actually
known as the CAG trinucleotide repeat expansion. This diseases are being caused the
mutation in HTT gene. This genes have the provenance of clear instructions for more way of
making protein which is called as hunting tin. The function is to extract the protein which is
unclear but have appearances to be an important part of nerve cells in the brains. The
mutation in the HD gene is discovered to be increase CAG reparation which is also being
called as the terms of genetic stutter. This is considered as the progressive brain disorder
which is being caused by single defective gene in the chromosome 4 which is one of the 23
human chromosome pairs. This pair carries the person entire level of genetic codes. It is
observed that most gene disorders are rare, yet they affect various people with the simple
inheritance process. This defect is considered to be dominate which have meaning that
anyone who have inherited it forms respective parent with Huntington's will eventually
develop the disease. In people who don’t have Huntington’s disease this section of CAG
repeats in the gene is usually only repeated 10 to 35 times. On the other hand if the vice verso
situation have tens place, the section will ave repetitiousness of over 36 times and have the
chances to be repeated more that 120 times. This have the leading of productiveness of
abnormally along version of the Huntington's proteins. The longer version is latter on cut into
smaller and toxic level of fragment which are latter on accumulated together and disrupts as
the normal function of nerves elk in ore respective manner. The greater numeracy is the
reputation is there, the earlier in onset is considerate of diseases with serious level of
outcomes.
There is multiple low-level of changes in the terms of cellular ones as the toxic
functions of mHTT may manifest and produce the HD pathology. The mutant has type the

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protein is more prone to cleavage that creates shorter fragments containing the poly
glutamine expansion
Deltas (2018) defines that diseases inherited mutation from a single gene often
follows a simple pattern that depends on the location of the gene. This single gene disorder
pattern is referred to as Mendelian inheritance. It is observed that most gene disorders are
rare, yet they affect various people with the simple inheritance process. The autosomal
dominant disorder is a single gene disorder that suggests that for each affected person in the
family, there has to be an affected parent that is responsible for genetic disorders. Common
diseases from the autosomal dominant process include “achondroplasia, familial
hypercholesterolemia, Huntington’s disease, and neurofibromatosis”. Based on the findings
of Cornec-Le Gall et al. (2018), genetic disorders due to autosomal dominant mode are
caused by genes on the autosomes that are non-sex chromosomes. Children inherit two copies
of autosome one from each parent that contains 22 autosomes contributing to most of the
genes of the child. The term dominant is referred to in the context that suggests that children
will get the genetic disorder if they contain only one disease-causing copy of a gene. It is
identified that unless the mutation occurs, every affected individual will have one affected
parent. The autosomal dominant mutations continue for a generation due to the affected
parent; however, it could also occur for the first time due to spontaneous gene mutation
(Deltas, 2018).
Applications and Impact of Cell Biology, Genetics and Biochemistry in Diagnosis of
Huntington’s disease
Diagnosis of Hutingtons disease can be done with the help of doing genetic test. This
test is useful to check the presence of abonornally expanded hutingtons diseasegenee. It has
been analysed that helath care professionals who are engaged in looking upon this will first
make sure that if patient has family history of hutington disease or not. They will also be

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engaged in evaluating other signs and symptoms of this disease. This disease can reduce
mental and physical abilities of services users, making there health conditions more
worsening. This disease is been caused by inherited mutation that gives indtructions so that
HTT protein can be made up in body (Caron, Wright and Hayden, 2018). It has been
analysed that if parents are sufferimg from this problem then there are 50% chances that child
will also suffer from it. It has been identified that one copy of the mutated gene is really
sufficient to increase this proble,. Diagnosis that has been suggested by helath care
professionals in order to cure this problem includes symptomatic testing. In this clinicians are
engaged in identifying the signs and symptoms of Hutingtons disease. It is major part of their
diagnosis. In this test health care professionals are engaged in identifying the changes in
motor function, also they are involved in doing neuropsychological assessments on which
they are looking for changes that are cognitive. Psychiatric evaluation are also being done in
order to assess behavioural changes. In order to detect the exavt problem helath care
professional can also get engaged in making patient do MRI. This is basically done by them
to evaluate changes which brings out Hutington’s disease that has been caused in the brain.
This conditions also affect brain. Sampling of blood can also be take by helath care
professional. Huntington’s disease will almost always be present in people with 40 or more
CAG repeats. It is really essential for service users to under go this testing or can also
engaged in consulting a genetic counsellor. This can assist them in better understanding the
impact of results on person suffering form Hutington’s disease and also can impact patients
family. This disease is basically a genetic disorder which has been inhereited from parents.
Despite recent development, there is still a lack of development research on the
application of diagnosis of Huntington’s disease. There is still no significant cure to the
targeted genetic disorder, yet the recent development is going at the genetics level to find a
cure for the disease. However, the impact of biochemistry can be observed in the form of

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different medications made for Huntington’s disease. But these medicines only help in
controlling the symptoms of Huntington’s disease and do not eradicate the disorder (NINDS,
2020). Majority of the medicines utilised in the HD symptoms work by modulating the
transmitter. Tetrabenazine is often prescribed medicine in the case of HD as it causes
depletion of the neurotransmitter dopamine. It is also suitable for treating Huntington’s
associated involuntary movements. Since the HD disease affects mental abilities,
antipsychotic drugs such as clonazepam that are helpful in controlling the hallucinations,
delusion and violent outbursts. However, these drugs are not suitable for the muscles
contractions that cause repetitive movements and in the worse scenario could even cause
stiffness and rigidity in muscles. Other drugs include tranquiliser that is helpful in the cases
of depressions and prevents mood swings of the person. Often memory loss is considered as
the symptom of a drug reaction or diseases that makes it difficult to cure the treatment
(NINDS, 2020). However, there is development observed with regards to the two therapeutic
applications, including gene therapy and stem cells in order to mitigate the influence of
Huntington’s disease.
Gene Therapy
The method of gene therapy involves treating the human with a specific sequence of
DNA. It is a unique treatment that is still in the development phase; however, it will have a
serious influence on the diagnosis of Huntington’s disease (HTT disease). There are two
approaches considered for the treatment that is either to remove the defected gene from the
affected person or to replace the mutated gene with a healthy one for the prevention of
disease (Miniarikova et al., 2016). The genetic instructions would be delivered to the patient
through microbial vectors that are often derived from viruses due to their ability to penetrate
cells to deliver genetic material. It was studied that RNA can also change the functionality of
the gene. Thus, with gene therapy, the vector would be inserted into the microRNA to limit

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the production of HTT protein. Another approach considered for gene therapy is antisense
oligonucleotide therapy (ASO) that alters the functionality of cells. Synthetic DNA or RNA
would be injected in the ASO therapy to block the toxic effect of the harmful gene
(Miniarikova et al., 2016).
Stem Cells
Stem cells are useful that help to evaluate the molecular disease mechanisms. The
HTT affect the pluripotency state in adults that stop the development of nerve cell, muscles,
bones and embryonic development. Therefore, scientists have developed the model for
reactivating the pluripotency state by genetic programming. There is also research that
focuses on the transplantation of nerve cells derived from stem cells to mitigate the HTT
disease; however, no real achievement is achieved in the process. The major hindrance in the
development of stem cells treatment is because of brain function. The researchers can
introduce pluripotent stem cells with the HTT disease into the person's brain after mitigating
HD mutation. However, due to the complex connections that the brain makes with neurons, it
is currently impossible to form a connection for the transplanted gene with the brain
appropriately to counter the effect of HTT protein. There is a significant development in
another scenario where scientists are focusing on reawakening the damaged cells by
delivering specific growth. However, these strategies have not offered much success due to
brain stem cells and their functionality (Ring et al., 2017).
Conclusion
The essay evaluates the structure of genetic material and describes the method for its alteration
through natural and artificial means. Later, the mode of inheritance for the genetic order has been
discussed that focus mainly on the autosomal dominant method. In the autosomal dominant mode,
every affected person has the affected parents, and it was evaluated that diseases due to this mode of
inheritance continue for a generation until altered due to mutation. Finally, applications related to the

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diagnosis of HTT disease caused due to autosomal dominant were discussed. It was thus evaluated that
although there is no significant cure to the disorder, yet major development is in progress in the form of
gene therapy and stem cells to counter the effect of HTT disease. It has been summarised that
hutington’s disease can be cured by neurological, psychological and genetic testing. These are also
known as direct genetic test. In these type of test they count the number of CAG which repeats in HD
gene. DNA is been extracted from sample of blood of patient. If service user has family history of HTT
then prenatal testing can be taken as an option. This method provides higher rate of certainity. This
shows whether the fetus is affected or not, so that further treatment can be done.

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