Type 1 diabetes is a chronic disease in which there are high levels of sugar in the blood. While type 1 diabetes can occur at any age, it is most often diagnosed in children, adolescent, and young adults. Type 1 diabetes is a complex, multigenic disease. Nearly 40 years ago, the first reports of genetic association to type 1 diabetes were for the human leukocyte antigen region. Since then, researchers have not only been trying to pinpoint which alleles of human leukocyte antigen-encoding genes are responsible for type 1 diabetes association, but also which other genetic loci contribute to the type 1 diabetes risk. Human leukocyte antigen does not refer to a single genetic locus, but rather a region of the genome, containing less than 6543 unique allele sequences. There is also a strong association between type 1 diabetes and polymorphism in the promoter region of the insulin gene. Part of what makes sorting through human leukocyte antigen associations so difficult is the extremely large numbers of reported alleles at the human leukocyte genetic loci as well as differences in allele frequencies and haploid combinations among populations, incomplete penetrance of the human leukocyte antigen susceptibility loci, and epistatic interactions with other susceptibility factors. For some alleles of human leukocyte antigen, the risk of type 1 diabetes is determined by specific combinations of alleles, rather than by genotype. Multiple haplotypes are positively associated with type 1 diabetes, while many others are negatively associated. Specific genotypic combinations are also associated with increased risk, although still not the main cause. Maintaining a consistent nomenclature among scientists has been very challenging with the extreme polymorphism of the human leukocyte antigen-encoding loci. There has also been a dramatic increase in the number of reported human leukocyte alleles with new and better genotyping technologies, which adds to the challenges faced by modern scientists. There are dozens to thousands of alleles that exist for each human leukocyte antigen gene. In order to establish other genes in the human leukocyte antigen region as potential type 1 diabetes risk loci, scientists must first demonstrate an observed association in the human leukocyte region is a true disease susceptibility effect, and not only due to linkage disequilibrium. Currently, it is believed that type 1 diabetes results from an initial triggering event. This is followed by gradual autoimmune destruction of the pancreatic β cells, until the residual β cells are insufficient to meet the insulin demands of the body. Since the trigger of type 1 diabetes is unknown, the autoimmune process is usually undetected until the time of diagnosis. The rate of autoimmune destruction is unknown, and could vary among individuals. The end of the autoimmune process is marked by the destruction of pancreatic β cells by cytotoxic T cells. Even after almost forty years of research, human leukocyte antigen is still the strongest predictor of risk for type 1 diabetes, with reported odds ratios ranging from 0.02 to less than 11. However, the genetics of type 1 diabetes is more complex than any scientist could have predicted. Therefore, while scientists know quite a bit about the genetics of susceptibility to type 1 diabetes, more data is necessary to determine where the link is.
Works Cited:
Noble, Janelle A., and Henry A. Erlich. "Genetics of Type 1 Diabetes." PubMed Central. Cold Spring Harbor Perspectives in Medicine, Jan. 2012. Web. 13 Feb. 2012.
Ashley Sisk
With type 2 diabetes not being quit as serious as type 1, are the same genes linked to each of these disease. I understand that type 1 is a much more sever case, but do the genes in which control this whether you have this disease look the same or at least simliar. Or are there just sligh motifications or differences in a string of genes that are linked to this chronic disease?
ReplyDeleteHannah Shumaker
Type 2 diabetes still has some genetic links, although researchers are still unsure of where the link exactly is, even in type 1 diabetes. The main differences between the two is type 1 diabetes generally appears at a young age, so we associate this with juvenile diabetes. It's true type 2 generally has to do with an unhealthy lifestyle, but there are still genetic links. Basically, with type 2, someone is genetically predisposed, and an unhealthy lifestyle just increases the risks of actually getting it. This is not only why we can see type 2 diabetes in healthy, more elderly, but why you sometimes hear the term "borderline type 2". I attached a link to an article about type 2 diabetes if you're interested in learning more. There is also a link from that page for type 1 diabetes so you can really see the differences.
Deletehttp://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001356/
-Ashley Sisk
From what I understand from research type 1 and 2 diabetes do no involve the same genes. Type 1 diabetes is when the body does not produce any insulin. This cannot be reversed and is not usually caused by a person's lifestyle. There for this would have to do with a genetic trait. Type 2 diabetes is when a not enough insulin is being produced or when the insulin is not working as it should. Type 2 diabetes is usually due to a unhealthy lifestyle and appears later in life. This makes me think think that genetics do not really play a large role in type 2 diabetes. Again this is what I interpreted, feel free to read the link I attached for yourself.
ReplyDeleteM. Castaneda
http://www.medicalnewstoday.com/articles/7504.php
This blog was very interesting in that we know so much about this disease, and yet we still cannot form a cure or even get a definite confirmation as to whether a person will have the disease or not and whether their children will inherit the disease. I just find it fascinating that there is so much we know out there but a million times more that we still have to learn.
ReplyDelete-Kara Ward