Sickle Cell Anemia: A Biology Report on Genetics and Symptoms

This report provides a comprehensive overview of sickle cell anemia, a homogenous anemic disorder caused by a mutation in the hemoglobin gene. It delves into the genetic aspects, including the substitution of valine by glutamic acid, and the autosomal recessive inheritance pattern. The report explores the prevalence, signs, and symptoms, such as sickling of red blood cells, shortness of breath, and fatigue, and the genotypic (SS, AS) and phenotypic characteristics. Diagnostic methods like blood tests are discussed, along with treatment options such as stem cell transplants, bone marrow transplants, and blood transfusions. The report highlights the prevalence of sickle cell anemia in various populations and emphasizes preventive measures like avoiding marriages between carrier partners. The discussion also includes the probabilities of inheritance and the implications for carriers. The conclusion underscores the importance of medical interventions for managing the condition, particularly in adults, and the potential for curative treatments in children. The report includes a bibliography of relevant sources.

Sickle Cell Anemia
Biology
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Introduction
Sickle cell anemia is a homogenous type of anemic disorder which is caused when the
amino acid valine gets mutated and substituted by glutamic acid in amino acid chain coding
for hemoglobin (Jan C. ter Maaten, 2010). This report discusses the sickle cell anemia and
various aspects related to it such as its prevalence signs symptoms and its genotypic and
phenotypic characteristics. It also focuses on the measure that can be intervened to prevent its
transmission.
Review
Sickle cell is a genetic disorder that is triggered due to the mutation in the single
nucleotide in the gene and hence affecting the hemoglobin molecule in RBC in blood that
delivers oxygen gas to all different cells of the body parts. Single gene genetic disorder is
defined as the disorder caused due to change in only a single gene. It has been studied that the
sickle cell anemia trait is present on the recessive allele of the hemoglobin gene, which
indicates that there are two allelic copies of the recessive gene which are inherited from the
parents. Hence, it is a recessive allele disorder. It shows an autosomal type of recessive
pattern. The trait which is visible in an organism is called a dominant trait while which is
present in the gene but is not expressed is called a recessive trait. Moreover, traits that are
carried on the chromosome numbered 1 to 22 that do not determine the sex of the individual
are autosomal traits while those carried on the chromosomes X and Y are sex-linked
chromosomes (Odièvre, 2011).
The person with one allele as dominant and other one allele as recessive is a carrier of
the trait but does not have the disorder. In normal conditions, a person receives two copies of
the gene from its parents that significantly produces the beta-globin which is present in
hemoglobin. However, in the case of single-cell anemia person inherits one normal allele

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from one parent and one abnormal or mutated allele from another parent which encodes for
the hemoglobin S and makes its genotype AS. Individual who have genotype as AS have the
sickle cell anemia in the form of diseases and show its full-fledged symptoms and phenotypes
which means the characteristics that are visible as signs, whereas a person with genotype as
SS have the sickle cell anemia in form of trait, which means they are only carriers of the gene
but do not have the disorder but can be transferred to their progeny (Elkins, 2013).
Genotype is the organism’s hereditary information, while phenotype is the visible
characteristic. Symptoms include sickling of the red blood cells causing the anemic condition,
shortness of breath, delay in growth of the child and fatigue (Steiner, 2019).
Blood test diagnostic in the laboratory helps in finding the structure of the RBC in the
blood samples with the help of the test that looks for sickling traits. In children and
adolescents, it is recommended to get treated by stem cell transplant and bone marrow
transplant as it has chances to cure the disease. While in adults, it can only be managed by
preventing an episode of pain and fatigue. Moreover, blood transfusion can also be
intervened (Sickle Cell Disease: Advances in Treatment, 2018).
Sickle cell is by far the most prevalent hereditary condition in several parts of the US,
where it affects around 70 to 80 thousand Individuals. The illness is reported to have existed
in African Americans with 2 percent chances and by 1 percent in Hispanic Americans. Sickle
cell disorder impacts millions of people around the globe. This is most popular in citizens
whose roots originate from Africa or the European countries and areas including, South and
Central America. The incidence rates can be prevented by reducing the cases of marriage
between two sickle cell trait carrier partners. As, it can show up in their progeny as well.
Homozygous defines as the presence of two copies of the same allele while heterozygous
means the presence of two different alleles for a gene. After studying the Punnett square of

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two heterozygous parents with sickle cell allele carrier, it can be denoted that the genotype of
SS: Ss: ss is in the ratio of 1:2:1 (Kurz, 2020).
(Elkins, 2013)
Discussion
Sickle cell is an autosomal recessive disorder that is usually genetic in the majority of
cases and is inherited from the parents to their progeny. There are 25 percent chance of
getting infected with the disorder and a 25 percent chance of not getting even a carrier allele.
However, the rest 50 percent indicates that the progeny can be carriers of the sickle cell trait
and can transfer it to their progeny as well.
Conclusion
It can be concluded from the discussion that sickle cells can only be prevented by
medication and blood transfusion interventions in adults, which only manages the condition
and prevents worsening of the symptoms but the person has to live with it. While in the case
of children, bone marrow and stem cell transplant may give satisfactory results.

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Bibliography
Elkins, K. M. (2013). Human Genetic Analysis. Forensic DNA Biology. Retrieved from
https://sites.google.com/site/prettyeasybio/genes-vocabulary/punnett-squares
Jan C. ter Maaten, F. A. (2010). Sickle Cell Disease. Comprehensive Clinical Nephrology .
Kurz, T. L. (2020). Probabilities of Sickle Cell Disease. Mathematics Teacher: Learning and
Teaching, 113(2), 152-155.
Odièvre, M. H.-P. (2011). Pathophysiological insights in sickle cell disease. The Indian
journal of medical research, 134(4), 532.
Sickle Cell Disease: Advances in Treatment. (2018). The Ochsner Journal, 18(4), 377-389.
Steiner, R. (2019). A Living Physiology. Waldorf Library.