Chromosome+14

__**CHROMOSOME #14**__

 * Size of Chromosome**: [|106 million base pairs]


 * Excerpt from //Genome//:**

"Yet so long as the earth exists in something like its present state, some creature somewhere will be an ancestor of future species and the immortal chain will continue" (Ridley, 1999, p. 196).


 * Gene 1 -** [|PNP] **(Purine Nucleoside Phosphorylase)**



Scientific Terms
 The //PNP// gene provides instructions for making an enzyme called purine nucleoside phosphorylase. This enzyme is found throughout the body but is most active in specialized white blood cells called lymphocytes. These cells protect the body against potentially harmful invaders by making immune proteins called antibodies that tag foreign particles and germs for destruction or by directly attacking virus-infected cells.  Purine nucleoside phosphorylase is known as a housekeeping enzyme because it clears away waste molecules called deoxyinosine and deoxyguanosine, which are generated when DNA is broken down. Specifically, purine nucleoside phosphorylase converts deoxyinosine to another molecule called hypoxanthine, and converts deoxyguanosine to another molecule called guanine ("PNP," 2012).

Layman's Terms:
 This gene codes for an enzyme called purine nucleoside phosphorylase which can be found in specialized white blood cells that protect the body from harmful intruders called pathogens. White blood cells make antibodies that attack the pathogens and infected cells. When the white blood cells break down the DNA from the pathogens or infected cells, waste molecules called deoxyinosine and deoxyguanosine are produced. PNP's role is to clear them away by converting them into new molecules called hypoxanthine and guanine.

Purine nucleoside phosphorylase gets rid of wastes that can be very harmful. If this enzyme did not do its job, deoxyguanosine triphosphate builds up which can be toxic for white blood cells. The white blood cells undergo apoptosis and the immune system is impaired.
 * Why is purine nucleoside phosphorylase?**



**Gene 2 -** [|SERPINA1] **(Serpin Peptidase, Inhibitor, clade A (alpha-1 antiproteinase, antitrypsin), member 1)**



Scientific Terms:
 The //SERPINA1// gene provides instructions for making a protein called alpha-1 antitrypsin, which is a type of serine protease inhibitor (serpin). Serpins help control several types of chemical reactions by blocking (inhibiting) the activity of certain enzymes. Alpha-1 antitrypsin prevents the digestive enzyme trypsin from breaking down proteins until trypsin reaches the intestines. Alpha-1 antitrypsin also inhibits other enzymes, including a powerful enzyme called neutrophil elastase that is released from white blood cells to fight infection.  Alpha-1 antitrypsin protects the lungs from neutrophil elastase, which can damage lung tissue if not properly controlled. Alpha-1 antitrypsin is produced in the liver and then transported to the lungs via the blood. ("SERPINA1," 2012)

Layman's Terms:
 This gene codes for a protein called alpha-1 antitrypsin (AAP). AAP blocks the activity of certain enzymes such as neutrophil elastase, which are produced by white blood cells to fight infection. AAP is produced in the liver and transported to the lungs through the blood. If the protein cannot escape the liver and prevent the elastase from harm lung tissue, causing emphysema and liver disease.

Alpha-1 antitrypsin prevents substances that can be harmful at moments. For example, if AAP is not able to do its job, substances such as neutrophil elastase can damage the lungs and can cause emphysema.
 * Why is <span style="font-family: Arial,sans-serif;">alpha-1 antitrypsin important? **



<span style="font-family: Arial,sans-serif;">**Genetic Disease - [|Krabbe Disease] (Globoid Cell Leukodystrophy)**

<span style="font-family: Arial,sans-serif;">



<span style="font-family: Arial,sans-serif;"> **WHAT IS [|KRABBE DISEASE]?** <span style="font-family: Arial,sans-serif;"> Krabbe disease is a disorder that affects the nervous system. It is caused by a mutation in the GALC gene. The effect of the mutation causes there to be a shortage of galactosylceramidase which damages the growth of myelin, which protects the nerve cells and promotes the movement of nerve impulses. Without proper a myelin sheath nerve impulses cannot travel properly, which is vital for the nervous system. Because it affects the myelin, it is classified as a leukodystrophy. <span style="font-family: Arial,sans-serif;"> **WHAT ARE ITS SYMPTOMS?** <span style="font-family: Arial,sans-serif;"> The age of onset of Krabbe disease is before the age of one. Some symptoms include irritability, muscle weakness, feeding difficulties, fever, infection, stiff posture, and slow mental and physical development. In addition, the infant's ability to move, chew, swallow, and breathe is affected. However, Krabbe disease can also occur during childhood, adolescence, and adulthood. Krabbe disease is lethal. <span style="font-family: Arial,sans-serif;"> In the United States, 1 in 100,000 persons are diagnosed with Krabbe disease.
 * HOW COMMON IS IT?**

<span style="font-family: Arial,sans-serif;"> **HOW IS KRABBE DISEASE DIAGNOSED?** <span style="font-family: Arial,sans-serif;"> Krabbe disease is diagnosed by testing skin cells or blood sample. The levels of galactosylceramidase are measured to see if the person has Krabbe disease.

<span style="font-family: Arial,sans-serif;"> **HOW IS KRABBE DISEASE INHERITED?** <span style="font-family: Arial,sans-serif;"> Krabbe disease is autosomal recessive and both parents must be carriers of the mutation. As a carrier, the parent will not show any symptoms.

<span style="font-family: Arial,sans-serif;"> **[|HOW IS KRABBE DISEASE TREATED?]** <span style="font-family: Arial,sans-serif;"> There is no cure for Krabbe disease but parents who are carriers of the gene abnormality can undergo genetic counseling. When the baby is born, it can be screened if it is affected by the disease and the newborn can be treated with care.

<span style="font-family: Arial,sans-serif;">[|INTERESTING FACT:]

>
 * Chromosome 14 has has 393 psuedogenes, sequences that may seem like a gene but no longer serves a purpose.
 * 96% percent of these pseudogenes may have served a purpose by comparing them to genes of other species such as the mouse and freshwater pufferfish.

>>> =REFERENCE=

<span style="font-family: Arial,sans-serif; font-size: 10pt;"><range type="comment" id="975476">1. Chromosome 14 - Genetics Home Reference. (2012, May 7). //Genetics Home Reference - Your guide// //<span style="font-family: Arial,sans-serif;">to understanding genetic conditions. //Retrieved May 9, 2012, from http://ghr.nlm.nih.gov/chromosome/14 2. <span style="background-color: #ffffff; font-family: Tahoma,Geneva,sans-serif;">Ridley, M. (1999). // Genome //. London: Fourth Estate. <span style="font-family: Arial,sans-serif; font-size: 10pt;">3. PNP - purine nucleoside phosphorylase - Genetics Home Reference. (2012, May 7). //Genetics Home// //<span style="font-family: Arial,sans-serif; font-size: 10pt;">Reference - Your guide to understanding genetic ////<span style="font-family: Arial,sans-serif; font-size: 10pt;">conditions. //<span style="font-family: Arial,sans-serif; font-size: 10pt;"> Retrieved May 10, 2012 from http://ghr.nlm.nih.gov/gene/PNP <span style="font-family: Arial,sans-serif; font-size: 10pt;">4. SERPINA1 - Serpin Peptidase, Inhibitor, clade A (alpha-1 antiproteinase, antitrypsin), member 1 - Genetics Home Reference. (2012, May 7). //Genetics Home// //Reference - Your guide to understanding genetic conditions//. Retrieved May 10, 2012 from http://ghr.nlm.nih.gov/gene/SERPINA1 5. <span style="font-family: Arial,sans-serif;">Krabbe disease - Genetics Home Reference. (2012, May 7). //<span style="font-family: Arial,sans-serif;">Genetics Home Reference - Your guide to understanding genetic conditions //<span style="font-family: Arial,sans-serif;">. Retrieved May 11, 2012 from http://ghr.nlm.nih.gov/condition/krabbe-disease <span style="font-family: Arial,sans-serif;">6. <span style="font-family: Arial,sans-serif; font-size: 10pt;">Krabbe disease: Prevention - MayoClinic.com (n.d.). // Mayo Clinic //. Retrieved May 12, 2012, from http://www.mayoclinic.com/health/krabbe-disease/DS00937/DSECTION=prevention 7. <span style="font-family: Arial,sans-serif;">Edward. (n.d.). Another human chromosome is finished. //<span style="font-family: Arial,sans-serif;">Genome News Network //<span style="font-family: Arial,sans-serif;"> - //<span style="font-family: Arial,sans-serif;">Home //<span style="font-family: Arial,sans-serif;">. Retrieved May 12, 2012, from http://www.genomenewsnetwork.org/articles