Hereditary Fructose Intolerance: A Nutritional Biochemistry Report

This assignment provides a detailed analysis of hereditary fructose intolerance (HFI), explaining why individuals with HFI are unable to metabolize fructose. It begins by describing the normal metabolic pathway of fructose, starting from its chemical structure and progressing through digestion, absorption, and enzymatic processing, including oxidation to produce ATP. The assignment then provides a concise overview of HFI, covering its origins, consequences (dysregulation of the metabolic pathway), major symptoms, and prevalence. Furthermore, it explores genetic mutations, mutagenic agents (both chemical and physical), and their impact on DNA. The document concludes by listing relevant references used in the analysis. This assignment showcases the application of biochemical principles in understanding a specific metabolic disorder and the broader implications of genetics and mutagenesis.

NUTRITIONAL BIOCHEMISTRY AND PHYSIOLOGY
Name
Institution

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NUTRITIONAL BIOCHEMISTRY AND PHYSIOLOGY
This paper responds to the short questions that deal with the hereditary fructose
intolerance and the mutagenesis agent. The first part covers the short questions of the hereditary
fructose intolerance. The second part deals with the questions of the mutagenesis agents.
1) HFI is a condition where the body fails to produce the chemical needed in the
metabolism of fructose in the liver. The body normally absorbs fructose that is in the intestine. In
the liver, there is lack of enzyme classification code EC 2.1.2.13 that is the main enzyme useful
in the metabolism of fruit sugar. 7 Ingested fructose is then transformed to fruit sugar-1-
phosphate. After that, it is converted to glyceraldehyde-3-phosphate through metabolism.
Glyceraldehyde-3-phosphate is the energy-producing element in the body. 3
The entry of the carbon atoms of fructose into the pathway of glycolytic that are in the
kidney, small intestine and hepatocytes is defined below.

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An absence of this enzyme causes fructose-1-phosphate to accumulate in the kidney,
small intestine, and liver. The accumulation of fructose-1-phosphate prevents the breakdown of
glycogen and the synthesis of glucose, thus causing hypoglycaemia after absorption of fructose.
The condition of Hypoglycemia occurs typically to those who have diabetes, and it’s
accompanied by the presence of low blood sugar in the body. Other symptoms include the
following: vomiting after ingestion of fructose and increase pain in the abdominal.6
2) HFI is a generic growth disorder that inhibits an individual from digesting fructose (a
form of sugar usually found in honey, fruits). The condition begins in infancy, and any
consumption of fructose causes nausea, abdominal pain, low blood sugar, as well as vomiting.
The disorder is caused by the imperfect mutation of the gene that is found on chromosome 9.
HIF condition takes place when the body lack aldolase B in the body.
The enzyme is responsible for breaking down fructose. If an individual without the
aldolase B enzymes consumes sucrose or fructose (table sugar, beet sugar or Cane), complex
chemical changes happen in the body. This prevents the body from converting glycogen into
sugar. This enables concentration of dangerous substances in the liver, and the level of blood
sugar also falls in the body. HFI is inherited, and this means that it can be transmitted through
families.4
HFI has identified 35years ago; however fatal cases of the disease continue to occur in
Australia. In the recent years, occurrences of fructose poisoning and HFI death have been
reported in Australia.
Symptoms
1) Damage in the liver including enlarge liver, jaundice and chronic liver disease, 2)
There is poor feeding problem in the baby, 3) Initial sign is nausea, vomiting, swollen abdomen,

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diarrhea and low blood sugar. Finally, coma and Epileptic seizures may happen because of the
severe contact with fructose. 8
Additional information
HIF may sometimes bring confusion with a condition named as fructose malabsorption. It
is a situation that occurs when there is a reduction in the absorption of fructose, especially in the
intestine causing physiological problems. The condition is also known as dietary fructose
intolerance. Hereditary Fructose Intolerance is not related to Fructose Malabsorption.
Prognosis- HFI may be severe or mild. Avoiding sucrose and fructose assist most of the
children to avoid this condition. In most cases the prognosis is good.
Detection method- The two common detection method of HIF mutation A174D and
A149A is by Restriction Fragment Length Polymorphism test and Intravenous Fructose tolerance
test.
2) Genetic tries to describe the variations and mutation that is found in living organisms
by studying of molecules that help in the process of translation, transcription, hereditary patterns,
and gene expression. The most common molecular structure is RNA and DNA. 1
Mutation is a change that occurs in the DNA sequence of the living organism. The
process of mutation can be inherited from one generation to another generation. 5 The damage to
the DNA can happen due to the addition of chemical or structural interruption of DNA base
(creating nucleotide fragment or an abnormal nucleotide). Hereditary mutations can be inherited
from one generation to another and exist in the individual’s life cell. This kind of mutation is also
called germline mutations since they are found in the sperm cells and parent’s egg. 2
Mutagenic agents- mutations can be initiated by both chemical and physical means.

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Chemical mutagens- this intermingle directly with DNA by modifying the bases of the
nucleotide or acting as analogs of the nucleoside. Both the nucleotide bases and nucleoside
analogs can combine with the DNA during the process of replication. The base analogs initiate
mutations because they usually have different base – paring rules as compare to the bases they
replace. Another kind of chemical mutagens changes the normal bases of DNA, causing in
different rules of base-pairing. The example is the use of nitrous acid to deaminate cytosine, thus
changing it to uracil. After that, Uracil joins with adenine thru replication, stimulating the
conversion of the base pair of the GC to AT base pair.
Radiation- Exposure to nonionizing or ionizing radiation can initiate mutation in DNA,
via different mechanisms. Ionizing radiation such as gamma rays and X-rays can lead to double-
and single-stranded breakdowns in the DNA through the creation of hydroxyl radicals. The bases
can also be modifying the Ionizing radiation; an example is the deamination of cytosine to form
uracil with the help of nitrous acid.
Additional information
The rate of mutations in the body can be increased by being in contact with radiation,
harmful chemicals, insufficient nutrients (especially folate, B12, and B6) and build-up of
radicals.

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References
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