Genetic causes of type 2 diabetes

Add links
Source: Wikipedia, the free encyclopedia.

Most cases of type 2 diabetes involved many genes contributing small amount to the overall condition.[1] As of 2011 more than 36 genes have been found that contribute to the risk of type 2 diabetes.[2] All of these genes together still only account for 10% of the total genetic component of the disease.[2]

There are a number of rare cases of diabetes that arise due to an abnormality in a single gene (known as

maturity onset diabetes of the young (MODY), Donohue syndrome, and Rabson–Mendenhall syndrome, among others.[1] Maturity onset diabetes of the young constitute 1–5% of all cases of diabetes in young people.[3]

Polygenic

Genetic cause and mechanism of type 2 diabetes is largely unknown. However,

potassium inwardly rectifying channel, subfamily J, member 11), encodes the islet ATP-sensitive potassium channel Kir6.2, and TCF7L2 (transcription factor 7–like 2) regulates proglucagon gene expression and thus the production of glucagon-like peptide-1.[8] In addition, there is also a mutation to the Islet Amyloid Polypeptide gene that results in an earlier onset, more severe, form of diabetes.[9][10]
However, this is not a comprehensive list of genes that affects the proneness to the diabetes.

monocytes of affected individuals, contributing to an inflammation-prone environment that predisposes minor allele carriers to development of certain pathologies with an inflammatory component.[11]
rs7873784 was also associated with the abnormal
high-fat diet and from secondary complications of T2DM such as atherosclerosis.[11]

Most SNPs that increase the risk of diabetes reside in

noncoding regions of the genes, making the SNP's mechanism for increasing susceptibility largely unknown. However, they are thought to influence the susceptibility by altering the regulation of those gene expressions. Only few genes (PARG6, KCNJ11-ABCC8, SLC30A8, and GCKR) have SNPs in the open reading frame (ORF).[4] These SNPs in ORFs result in altering of the protein
function, and the altered function and therefore compromise the performances of the protein product causes increased susceptibility to the type 2 diabetes.

One of the examples of gene regulation in non-ORF SNPs that influences susceptibility is the changes in nucleotide sequence in

homeodomain containing transcription factor that regulates other genes,[13]
faulty regulations of those genes increase the risk of diabetes.

Another example of faulty gene regulation that influence the susceptibility is the SNPs in promoter regions of the genes. Gene like APOM and APM1 increase the risk of type 2 diabetes when there are SNPs in their proximal promoter regions. Promoters are sequences of DNA that allows proteins such as transcription factors to bind for gene expression, and when the sequences are modified, the proteins no longer bind as effectively, resulting in depressed level of gene expression. APOM is partly responsible for producing pre beta-high-density lipoprotein and cholesterol,[14] and APM1 is responsible for regulating glucose level in blood and fatty acid.[15] Decreasing the level these gene products reduce the body's ability to handle glucose, which leads to the increased risk of diabetes.

Since 2019 large sequencing studies have started to identify rare coding variants associated with type 2 diabetes risk, including variants in PAM and

MODY gene GCK (over 14-fold increased odds) and the gene GIGYF1 (4-6 fold increased odds).[17][18]

It is important to note that those discovered genes do not determine susceptibility to diabetes for all people or cases. As the risk of diabetes is combination of the gene regulations and the interplay between those gene products, certain genes may not pose a threat to increase the susceptibility. TCF7L2 is one of the well-studied genes for diabetes susceptibility in most populations. However, SNPs in TCF7L2 that would normally increase the risk of diabetes does not affect the susceptibility for Pima Indians. However, this gene is associated with regulating the BMI for Pima Indian population.[19]

Various hereditary conditions may feature diabetes, for example

neurodegenerative disorder that first becomes evident in childhood. It consists of diabetes insipidus, diabetes mellitus, optic atrophy, and deafness, hence the acronym DIDMOAD.[20]

While obesity is an independent risk factor for type 2 diabetes that may be linked to lifestyle, obesity is also a trait that may be strongly inherited.[21][22] Other research also shows that type 2 diabetes can cause obesity as an effect of the changes in metabolism and other deranged cell behavior attendant on insulin resistance.[23]

However, environmental factors (almost certainly diet and weight) play a large part in the development of type 2 diabetes in addition to any genetic component. Genetic risk for type 2 diabetes changes as humans first began migrating around the world, implying a strong environmental component has affected the genetic-basis of type 2 diabetes.[24][25] This can be seen from the adoption of the type 2 diabetes epidemiological pattern in those who have moved to a different environment as compared to the same genetic pool who have not. Immigrants to Western developed countries, for instance, may be more prone to diabetes as compared to its lower incidence in their countries of origins.[26] Such developments can also be found in environments which have had a recent increase in social wealth, increasingly common throughout Asia.

See also

  • Epigenetics of diabetes Type 2

References

  1. ^
    ISBN 978-1-4377-0324-5
    .
  2. ^
    S2CID 43548816
    .
  3. ^ "Monogenic Forms of Diabetes: Neonatal Diabetes Mellitus and Maturity-onset Diabetes of the Young". National Diabetes Information Clearinghouse (NDIC). National Institute of Diabetes and Digestive and Kidney Diseases, NIH. Archived from the original on 2008-07-04. Retrieved 2008-08-04.
  4. ^
    PMID 26551672
    .
  5. PMID 19020324
    .
  6. PMID 21142536
    .
  7. PMID 24412096
    .
  8. PMID 17429082
    .
  9. PMID 8772735
    .
  10. PMID 12706321
    .
  11. ^
    PMID 31785408
    .
  12. S2CID 21203147
    .
  13. PMID 26329304
    .
  14. S2CID 21156244
    .
  15. PMID 14749263
    .
  16. PMID 31118516
    .
  17. PMID 35177841
    .
  18. PMID 34732801
    .
  19. PMID 17909099
    .
  20. PMID 11554774
    .
  21. PMID 16987875
    .
  22. Dw.com
    . 25 August 2017. Retrieved 29 August 2017.
  23. PMID 10643689
    .
  24. ^ Corona, Erik. "Geneworld". World Wide Patterns of Genetic Risk for Disease. Stanford University. Retrieved 11 September 2013.
  25. PMID 22053022
    .
  26. ^ Cotran, Kumar, Collins; Robbins Pathologic Basis of Disease, Saunders Sixth Edition, 1999; 913-926.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Genetic_causes_of_type_2_diabetes&oldid=1188099083"