Chapter 2 : Comparison of the Two Types of Gene Therapy

Chapter 2 : Comparison of the Two Types of Gene Therapy

There are two types of the gene therapy; germline gene therapy, somatic gene thrapy.   In germline gene therapy, the scientists try to treat diseases by inserting a normal gene instead of the faulty one only in germ cells, which are the sperms and eggs. In fact, the modifications of germline genes can be passed through generations, which is very good. Why? Because modifying the abnormal genes for certain diseases  in one generation, will be passed to the second generation and we will be eliminating the disease from occurring and no one will suffer from this disease any more. Even though this is a good opportunity to eliminate diseases entirely from one family, this type of therapy is not being attempted because there are some concerns of the risks that germline gene therapy can make such as altering another normal gene and causing new defect. Another consideration regarding this type of gene therapy is that few people may use this therapy for genetic enhancement such as choosing eye color for their next generation or increasing beauty and intelligence, which will give them more opportunities than others and may raise moral issues.  

            In the second type of gene therapy, somatic cell, scientists try to modify a gene that is in the body cells such as introducing normal genes to skin cells, bone marrow cell, blood cells, and a lot more. Unlike germline gene therapy, this type cannot be passed through generations and it will only affect the individual who is being treated. Even though there are many obstacles facing the scientists in the field, like how to deliver certain gene to the target cell. There are many clinical trials in their late phases which promise that somatic cell  gene therapy approach will be an effective treatment to many human diseases in future.  

 References:

http://www.nejm.org/doi/full/10.1056/NEJM199310143291607

http://www.news-medical.net/health/Gene-Therapy-Types.aspx

Chapter 1: Introduction

Chapter 1 : Introduction To The Gene and Gene Therapy

What is a gene ?

            Genes basically are small molecules that carry our genetic information. Genes consist of many nucleotides that make up our DNA, and are normally found in thread like structure called Chromosomes. Those chromosomes are usually within the nucleus of each human cell. When the cell divide and produce new daughter cells, a complete set of chromosomes can be found in each daughter cell. Inside each cell of our body, there are two copies of each gene; one from each parent. The main function of our genes is that it gives the instructions of  synthesizing proteins and enzymes, which are important for the body functions and metabolisms. Sometimes, abnormal genes arises from mutations, which are alteration of the nucleotide sequence. As a result, the gene produce missing or un-functional proteins that may cause genetic disorders.

What is Gene Therapy ?

            Gene Therapy can correct the genetic defects that mutations may resulted by targeting the abnormal gene and inserting new one to the cell. If mutations in certain gene resulted in abnormal or missing proteins, then the protein will not be able to function normally.  Gene therapy can introduce a normal copy of the gene to make the protein functional. The first successful gene therapy was done by William French Anderson in 1990 at the National Institutes of Health (NIH). He was successfully able to treat a girl who was suffering from Severe Combined Immunodeficiency disease that is known of producing impaired immune function.  Nowadays, there are many patients receiving gene therapy correcting their faulty proteins and making them function normally. However,  gene therapy is a very challenging task.  For instance, scientists have to find ways to transfer a foreign gene to the human call, make the gene expressed, and finally avoid the immune response to this foreign molecule.

             

References :

http://ghr.nlm.nih.gov/handbook/therapy

Pierce, B. A. (2012). Genetics a conceptual approach. New York, NY: Kate Ahr Parker.