Example research essay topic: Damaging Effects Of Cystic Fibrosis – 1,033 words

Cystic fibrosis is a debilitating disease facing
many people today. At the present time there is no
cure available. According to the cystic fibrosis
foundation of America, cystic fibrosis can be
traced back as early as 1595. The first documented
case was not reported until 1936. One group of
people that seem to be affected the most by cystic
fibrosis is Caucasians. Recent statistics indicate
that 1 in 3,200 live causcasian births are
afflicted with cystic fibrosis.

For reasons that
are currently unknown African Americans have
aslightly lower chance of developing cystic
fibrosis usually 1 in 15,000 live births. Cystic
fibrosis remains to be a rare disease in the asian
population as well as the native American
population. In the United States there are 1,000
children born each year with cystic fibrosis.
Current numbers suggest that there is over 30,000
people in the United States alone living with this
crippling disease. In the United states
approximately 1 in 25 -30 people are carriers of
the mutated gene that causes cystic fibrosis
(Sheppard and Nicholson ). The cystic fibrosis
foundation of America has repoted that there is
over 10 million people who are possible carriers
of the mutated gene. Cystic fibrosis is an
inherited genetic disease.

In actuality cystic
fibrosis is an autosomal recessive disease(Lim and
Zeitlin). Cystic fibrosis is now considered the
most common genetic disease among Caucasians
(Sheppard Nichsoln). Although cystic fibrous tends
to display an ethnicity bias it does not have a
gender bias. The autosomal recessive disease
indicates that the mutated gene that causes cystic
fibrosis is not located on the sex chromosome. In
1989 the mutated gene that causes cystic fibrosis
was discovered, and this was one step closer to
understanding a disease that affects so many
people ( Sheppard and Nicholson). The mutated gene
is located on autosomal chromosome number 7 .

mutation occurs in the cystic fibrosis
transmembrane conductance regulator gene (CFTR).
At the present time researchers have concluded
that there are over 900 different mutations in the
CFTR gene (Sheppard Nicholson). The severity of
the disease is based upon the variations of
mutations that are expressed (Panesear). For
instance a gene with over 900 mutations can wreak
havoc on the human body causing a plethora of
problems. When a person is a carrier of the
mutated CFTR gene , and is paired with a
non-carrier the cystic fibrosis phenotype will not
be expresses. This is due to the recessive
characteristics of the disease. Cystic fibrosis
will be expressed if both parents are carriers for
the mutated gene.

The composition and the
functionality of what the CFTR has been a
continuous battle until recently. The CFTR protein
is a chloride ion channel (Mcauley and Elborn ).
The CFTR protein is composed of two transmembrane
spanning domains with two nucleotide-binding
domains called NBD1 and NB2, and a regulatory
domain (R) (Panesar). The regulatory or R domain
contains multiple target phosphorylation sites for
protein kinase A and C (Harris and Argent ). The
CFTR channel is regulated by cyclic adenosine 3, 5
– monophosphate (camp) (Pansear). Once the
regulatory domain has become phosphorylated , ATP
hydrolysis at the NBF domains is essential to
keeping the channel open (Harris and Argent).
Panesar describes the mechanics of the functioning
CFTR protein as follows: chloride ions enter the
cell against an electrochemical gradient coupled
to sodium by the sodium- potassium chloride ion co
ranspoter. The chloride ion then exits from the
surface via a channel down the gradient, which is
regulated, by camp.

The complete functioning of
and mechanics of the CFTR still remain a mystery.
The mutations that can occur in the CFTR are
broken down into five classes. Class I mutations
are characterized by the total absence of the
CFTR. Class II are believed to be associated with
possible defects in the trafficking and folding of
the CFTR. Class III is found to be responsible for
the abnormal regulation of chloride conduction in
fully processed CFTR. Class IV mutations have been
linked with decreased chloride conduction in fully
processed CFTR. Many aspecs of the functioning of
class V mutation are not completely understood
presently, but ther are believed to be associated
with CFTR synthesis( Lim and Zeittlin).

Class I
defects of the CFTR mutations are the result of a
premature stop codon which is believed to actively
interfere with translation of the CFTR (lim and
Zeitlin). The mosst common mutation that is
expressed in cystic fibrosis and seen in over 70%
of people is a class II mutation called delta
508(Lim zeitlin). The delta 508 mutation is abase
triplet mutation. This mutation actually deletes
the phenylalanine residue at amino acid 508 of the
CFTR protein (Mcauley and Elborn). The delta 508
mutation is generally seen in populations of
northern European decent (Pansear). The loss of
the phenylalanine residue lies within the first
nucleotide binding factor region of the protein
(Harris and Argent).

In this mutation the protein
becomes milocalized within the cell, and remains
in the endoplasmic reticulium (er) rather than
being transported through the intracellular
memberane. One current theory sugeststhat the
trafficking problem might originate from the
folding of the protein. This particuliar mutation
is responsible for the misfolding , and therefore
causes the protein to be rejected from sorting and
processing (Harris and Argent). Class III
mutations are able to function and undergo normal
trafficking to the plasma membrane , but are not
able to be stimulated by camp. Class IV mutaitions
are generally denoted by an abnormally low
chloride conductance in the apical plasma
membrane. Which is unable to be regulated by cAMP.
The concentration of the chloride conductance
plays a very important role in this mutation.

mechanism by which epithelia secrete electrolytes
is essential to this mechanism. The electolyes
that are typically secreted are Nacl, NaHco3, and
water. In the event the fluid secreated is
drastically reduced or inhibitedthe surface of the
epithelia begin to dehydrate. The dehydrarion of
the epithelia will eventually lead to an
accumulation od secretions such as mucus.(Harris
and Argent). ClassV mutations tend to be a little
milder then the other classes of utations. These
are the least common mutations found within the
CFTR gene, and are therefore the least

This mutation can be briefly
characterized by a reduction in the number of
normal CFTR proteins, and possibly a reduction in
chloride ion transport (Lin and Zeitlin)..

Research essay sample on Damaging Effects Of Cystic Fibrosis