Chromosome+18

= Chromosome 18 =


 * Size:** The size of Chromosome # 18, is 76 Million Base Pairs.
 * [|(Chromosome Size], May 13, 2012)**


 * Excerpt from Genome: [[image:http://img2.imagesbn.com/images/102640000/102646645.jpg width="210" height="321" align="right"]]**
 * "Consider a gene on chromosome 18 that suppresses colon cancer.**
 * We have already met it briefly in the last chapter: a tumour suppressor**
 * whose location has not quite been determined for sure. It was**
 * thought to be a gene called DCC, but we now know that DCC**
 * guides the growth of nerves in the spinal column and has nothing**
 * to do with tumour suppression."**
 * (Ridley, M., 1999)**

**1st Gene: DCC**



 * DCC Main Function:**
 * "This gene acts like a netrin 1 receptor which controls the start and stop of multiplication of cells. The transmembrane protein is a member of the immunoglobulin superfamily which is a large group of soluble proteins of cell adhesion molecules, it gets its name because cancer patients have a reduced amount or no DCC gene in their chromosome."**
 * [|(DCC], May 13, 2012)**


 * As mentioned by the author, this Gene is arguably a tumor suppressor in humans.
 * DCC stands for Deleted in Colorectal Carcinoma, but is usually known as Deleted in Colorectal Cancer.

**DPC4 Main Function:**
"DPC4 is very similar to a gene in the fruit fly, Drosophila malanogaster, which is needed to develop cells for a flies wings. The signals are part of the TGF-ß superfamily of signaling pathways. When scientists used a genetic strategy to remove the TGF-ß gene in a cancer cell, we found we had also inactivated the TGF-ß pathway. These pathways usually act to control the maturity of cells and the rate of which they grow and/ or die."

([|DPC4], **May 13, 2012)**

What does TGF-ß do?
"TGF-ß has a role in humans similar to that in other species, and most normal cells stop proliferating when exposed to TGF-ß. " Meaning that cells stop replicating when TGF-B is removed from their cells. ([|TGF-B]**, May 13, 2012)**

=**Disorder: Ring 18**=

**Diagnosis: This disease occurs when the top and bottom piece of the arm of a chromosome 18 is missing. The result is a ring shaped chromosome, like above. Therefore the disease is called Ring 18.**
([|Ring 18], **May 13, 2012)**

**Symptoms:**

 * **People with ring 18 usually have some cognitive disability, though the degree of impairment varies among individuals. Based on literature reports, people with ring 18 appear to have IQ scores ranging from mild to severe mental impairment. ([|Ring 18], May 13, 2012)**
 * In other words, the development of some skills with ring 18 may never occur or happen at a very slow pace.**
 * **Facial features of the affected infant are different from its family members. Though not usually noticeable, it is part of ring 18.**
 * **Their development is affected, but for the most part, it is just that individuals affected by ring 18 are small for their age and are slower at developing.**
 * **Affected patients, usually have a problem with their foot or back. Some develop scoliosis, but these are treated the same way a normal patient would be treated, with braces and therapy.**


 * How common is it?**
 * Since the 1960's there has only been fifty cases that have been reported, leading many to believe that Ring 18 is uncommon but still have very bad effects on individuals.

Severity:
The thing with Ring 18 is no two cases is ever the same. This means the severity of the disease can never be clarified. Some patients live to adulthood while some die in their early years.

Treatments:
There are treatments for this disorder to prevent anything severe from occurring, but since there have not been many cases, its not as serious as other genetic disorders.

=Interesting Fact:= ([|Fact], **May 13, 2012)**
 * **Chromosome 18 accounts for 2.7% of all DNA and the number of genes on Chromosome 18 can never be specified because all vary, scientists believe that it spans from 300 and 500 genes.**

References  Ring 18. (n.d.). //Chromosome 18 > Home//. Retrieved May 13, 2012, from http://www.chromosome18.org/TheConditions/Ring18/tabid/128/Default.aspx

Cell adhesion - Wikipedia, the free encyclopedia. (n.d.). //Wikipedia, the free encyclopedia//. Retrieved May 13, 2012, from http://en.wikipedia.org/wiki/Cell_adhesion

DCC - deleted in colorectal carcinoma - Genetics Home Reference. (n.d.). //Genetics Home Reference - Your guide to understanding genetic conditions//. Retrieved May 13, 2012, from http://ghr.nlm.nih.gov/gene/DCC DNARSS.com : Chromosome 18. (n.d.). //DNARSS.com : Genetics News//. Retrieved May 13, 2012, from http://www.dnarss.com/Chromosome_18.html

DPC4. (n.d.). //Johns Hopkins Pathology//. Retrieved May 13, 2012, from http://pathology.jhu.edu/pancreas/geneticsweb/DPC4.htm

Netrin-1 and its receptors in tumou... [Expert Opin Ther Targets. 2008] - PubMed - NCBI. (n.d.). //National Center for Biotechnology Information//. Retrieved May 13, 2012, from http://www.ncbi.nlm.nih.gov/pubmed/18620521